# PC Shuts down & unable to start up.



## thinsitu (Dec 22, 2005)

Here's the problem: when i use the computer for quite some time (30min or more) the PC just suddenly shuts itself down, i don't mean the windows shutdown process begins, i mean its like someone just pulls the plug out the back of my computer, once it shuts down it does not restart.

another problem, when i turn my computer on it doesn't get past the boot stage, it shuts down when the BIOS Pentium 4 picture comes up or even before that.
also when i leave the computer on standby and when i power it up again, it shuts down!
sometimes i cannot even turn my computer on! i have to try and try again until it finally boots and get put down becuase it shuts down at the BIOS picture:sad: 

my specs:
IC7-MAX3 motherboard
Pentium 4 2.8Ghz
Enermax PSU (460W)
SATA 120Gig harddisk
6600GT nvidia vid card
2 X 512Mb Geil RAM

CPU never heats up more than 55C

solutions i've tried: change power cord, brought new PSU, brought new CPU heatsink & thermal paste, re-seated RAM in different (correct) slots, scanned for viruses. no difference whatsoever! help me please!

btw Voltages- found in BIOS (noted down when PC booted)
CPU core voltage 1.48V
DDR voltage 2.59V
DDR VTT voltage 1.28V
AGP VDDQ voltage 1.52V
ATX +3.3V 3.29V
ATX +5V 5.08V
ATX +12V 12.00V
Battery Voltage 3.21V
Standby Voltage 5.06V

Voltages - Speed Fan Program (ran while using the PC)- Excluding above
VCOREA 1.50 V
VCOREB 2.59V
-12 V -8.33 V
-5 V -2.94V
+5VSB 5.62V
VBAT 3.22V


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## Ethan Allison (Dec 23, 2005)

Sounds like it has some temperature cutoff where it just kills the power to avoid a melt. I'm guessing it's around 50 deg. C based on what you said. Hope that helps.

Ethan


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## thinsitu (Dec 22, 2005)

thanks for your help, but how come the PC can't be turned on in the morning? at that time the PC's got to be cool.

could it be my SATA hard disk that's causing the problem?


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## bals_gadda (Jul 30, 2005)

Automatically shutting off is a different problem but not switching on in the morning may be due to powersupply problem.Check the powersupply or change the powersupply and checkout.


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## ZDarryl (Dec 13, 2005)

Sounds like an overheating auto shut down as well.

Maybe there is some safety feature that prevents computer from being restarted after auto shut down? Check you mobo manual. 

Is your system overclocked?

55 deg C is pretty darn hot for a Pentium CPU.

What speed is your RAM and what speed are you running it at?

Is your VC overclocked?


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## thinsitu (Dec 22, 2005)

with the morning stuff, my old PSU and new PSU has the same problem so it won't be a PSU problem.

i have overclocked nothing, now that i've installed new heatsinks my CPU temp is aroun 49-50c, is that high?

how do you check your ram speed?

how can it be an overheat auto-shutdown when i have a housefan blowing into my case everytime i use the comp, my vid card temp never goes above 41 and my cpu temp never goes above 52 now after i installed the new cooling system (this case, its the home-fan blowing onto PC)


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## ZDarryl (Dec 13, 2005)

Go into the bios and you will find your RAM speed (front side bus or FSB)

While in the bios check for an overheat auto shut down setting.

How do you know your vc temp and your cpu temps?

Do you know the temp of the air in your case?


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## Tumbleweed36 (May 14, 2005)

Hi thinsitu,

Nice to see you again. Kind of got busy earlier and could not get back to take a look.

I need to know if that temp 55c is at-rest or under stress. See what happens in that when you first turn on the set, there is a pretty good bunch of power hits that CPU and that can cause temperature shut down immediately. To be quite honest, that 55c is not acceptable for an at-rest computer. High temps can also cause shutdown while under-stress. What I would like to see, is you get it going and do something stressful like playing a game and check the temps before it shuts down. At idle is one thing, but under-stress can be a whole new ball game. Why not use speedfan to tell that, or if you have an onboard program, use that to report that. 

When it was put together, did you use Artic Silver or the factory pad to put the CPU and Heatsink together?

Tell you another thing you might try. If it shuts down under stress, take a regular fan and with the case side off, just blow it toward the heatsink and CPU and see if it still shuts down.

If we can pinpoint were the problem is, then we can get to working on fixing it.

Another thing I want you to look at.....Is the heatsink fan blowing down or pulling heat off the heatsink? We would also benefit if you talked about case cooling....where are fans, which direction are they blowing.

Hope I didn't miss something and you have already answered these questions, but if I did, then forgive....have been rather busy with the holiday coming up.....you know, honey do this, honey do that....etc.

Will await a reply so we can evaluate further.


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## thinsitu (Dec 22, 2005)

RAM speed is 200 (forgive me if the number's totally off, i saw a number with RAM in front so i wrote it down)

i don't quite understand what you mean by a good bunch of power hitting my CPU at the start.

55C is under 100% CPU usage for more than 1 hour.

when i play games i get around 49-52C

i used CoolMaster thermal paste along with a huge coolmaster heatsing (twice the size of stock heatsink), it is copper instead of alluminium so you can imagine what your saying if my CPU is overheating. (the current heatsink i'm using is normally used with overclockers, which i'm not overclocking)

well in the past year i've always got my case out on one side and have a house fan blowing...

heatsink fan i blowing into the CPU instead of sucking air out.

i've only got that fan along with 2 powersupply fans, the rest i disconnected seeing that the house fan i'm using can provide much more air-movement.

it seems that my problem is stemming from more than one root, first: i can't get my computer to turn on in the first place, in the morning i have to use some jump starting to get it up. but otherwise once the computer is on in the morning it seems as if it would stay on for a very long time until we hit about 11am, my computer would suddenly shutdown (i would be playing games then) and then, even though from now on the computer turns on just by pressing the power on button, it never quite gets past the boot stage, either it shuts down again before the Intel picture comes up or it shuts down while the picture is up. the only way to get it up again is by disconnecting the power cord from behind, leave the computer off for more than an hour, then turn it on, like this it will get through the boot stage but still the computer will turn off suddenly after about 30-40 min of usage.

now you might be asking why i have to pull the power cord out? well if i leave the computer alone for more than an hour with the power cord intact then i can still not turn it on again.

you see, this is really weird and i can only conclude that more than one component has gone wrong....

another something i've noticed, the computer only suddenly shuts down in programs with a lot of keyboard usage (such as games), even typing this post the first time made my computer shut down. and the fastest way to get it to shut down it seems is: turn the computer on, wait until windows fully started up, press shift key or capslock key in very quick succession and after about 20 hits the computer shuts down.??????????

edit- a update on the keyboard stuff, it seems that every time the computer shuts down (when using windows not while booting) i've pressed a key on the keyboard (any key) , so basically if i use no keyboard at all the computer takes much longer to shutdown and sometimes it can stay on forever. 

so: to shutdown my lovely computer, all you have to do is hit a key on the keyboard and you will be granted an instant shutdown.:dead: 
could this be a RAM problem, OS problem or motherboard problem or something else?

sorry again for the length, more info = better support.

thanks for your help:grin:


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## Tumbleweed36 (May 14, 2005)

thinsitu said:


> RAM speed is 200 (forgive me if the number's totally off, i saw a number with RAM in front so i wrote it down)
> 
> i don't quite understand what you mean by a good bunch of power hitting my CPU at the start.
> 
> ...


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## twajetmech (Jul 1, 2004)

Hello...from the begining of your post, the first thing I noted was how low your memory voltage is....I would try setting the DDR Ref voltage to 2.65 or 2.75 and see if that helps stability. You also noted that your keyboard seems to cause instant shutdowns....is it possible something had been spilled in the keyboard and is now causing a stuck key or short, bad cable or connector. Are all the jumpers (if any) on the mobo present and accounted for, such as the clr rtc and in the correct position. 55C is a bit hot, I know my own P4 will start to get flakey at that temp. You may also want to bump the cpu voltage to 1.50-1.55....uping the mem and cpu volts to those levels won't do any harm. I would also make sure the I/O shield is in secure, otherewise you could have grounding issues. If all else fails try runing the computer outside of the case on a piece of cardboard with just one memory dimm a hd and videocard...then look for a standoff that is misplaced, loose front panel connectors, swollen capacitors on the mobo, droped screw,etc. It would be nice if you could try another psu....Enermax are excellent psu's and its rare to have them fail, but not impossible and your 460 is certainly adequate...if your computer is pluged into a apc or surge protector....try pluging it into the wall socket directly, they do go bad after a while and may be a partial cause to your problem......Well, those are the first ideas that come to mind after looking at the thread....I will continue to look at this, and hopefully we can find a resolution


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## UncleMacro (Jan 26, 2005)

From your various symptoms, I would guess that you have a bad motherboard. I wouldn't worry about your CPU temp because a Pentium 4 has thermal throttling which slows the CPU down when it gets too hot. You can run a Pentium 4 with a dead heatsink fan and it won't crash. It will just slow down a lot. Most of your other symptoms could be explained by a bad power supply but you have the same problem with two different supplies so it's not that. Plus, if your observation about key presses hastening a crash is correct, then you'd figure the power supply isn't the problem since the power supply isn't going to see any noticeable change in load when you press a key. The keyboard controller is on the motherboard and in a chip which controls lots of I/O devices on the motherboard. If that chip is bad, anything could happen. Removing the power cord from the power supply removes the Vsb (standby voltage) which powers some things on the motherboard so removing the power cord allows them to get completely cold. Some problematic hardware will only work properly stone cold whereas other bad hardware will only work properly when warm. So removing Vsb could have an effect on a bad motherboard.

Has this machine worked previously without these problems and then the problems just recently started? Did you make any hardware or BIOS changes just before the problem started?

From what I've seen above my guess (that's all I've got) is:
1) Bad motherboard. Given that you've already replaced power supplies this seems like the most likely cause of your problems. Unfortunately, there's no way to be sure without swapping in another which is a big pain in the butt and it's very expensive if it turns on not to be the motherboard. If I were in your position (given that I'm extremely cheap) I'd take the machine apart and put it back together with the minimum possible hardware installed (floppy only, 1 stick of RAM only, keyboard, and all onboard devices disabled) and see if you can get the problem to recur just using MemTest86. Taking it apart and putting it back together will fix any shorts and make sure all of the cables and cards are reseated. If it doesn't crack up in MemTest86 then add the hard disk and boot to Windows and try again. If you're going to swap motherboards then you'll have to take it apart anyway. Running with a minimal configuration will at least allow you to exclude some unnecessary components as possible causes.
2) Bad power supply. You've already tried two supplies with the same result so there's little point in trying a third.
3) Bad CPU. This is possible but seems extremely unlikely.


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## thinsitu (Dec 22, 2005)

super thanks for all your help.

i already tried taking it out once and no diff, i'll try it again though.

i'm trying all what you said now... if it doesn't work then i'll tell you tommorow, what UncleMacro said was right- i'm don't have a lot of cash right now so i want to put buying a new motherboard, CPU and RAM last..

plugged into wall socket, no difference.

keyboard stuff: well i tried a different keyboard, no difference. give it a little burst on shift or caps lock and the computer will turn off again.

i'm just wondering: when i use the barebone motherboard technique (motherboard on cardboard) is it alright if i've got a high-end 6600GT nvidia running on it? i've got no vid on board so i need to plug it in.


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## thinsitu (Dec 22, 2005)

can someone please answer this question: could it be a bad RAM?


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## UncleMacro (Jan 26, 2005)

Oops. I assumed that you'd already done the basics. You should run MemTest86 overnight (at least eight hours) with no errors to declare you RAM okay.

A 6600GT is okay for "minimal configuration" mode if that's all you've got. The main goal is to run with the smallest number of devices (disk drives, onboard devices, etc.) possible. Then if it works, you add one device at a time until it starts croaking again. But if your "keyboard crash" method works consistently, then that sounds more like some kind of motherboard problem. You might try fiddling with the keys while MemTest86 is running and seeing if that causes the same problem. If you can get it to crash in MemTest86 then that would rule out Windows or any driver problems as the cause.


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## thinsitu (Dec 22, 2005)

a good bit and a bad bit want to hear what first?

ok i know you want the good.

well i brought a new mother board at last and everything is working properly, i can start up the computer YAY!!

the VERY BAD bit:

when i was installing the CPU into the new mother board i found two pins broken loose, O_O, i think my CPU is screwed, however when i turn it on, it got past boot stage and went to windows boot, but the problem is i cannot load windows, i press start with safe mode but then the computer suddenly restarts.

how do you determine a blown CPU, i though the BIOS screen would show: CPU is unworkable or changed please enter BIOS menu.

and will a broken CPU get past boot stage? i though the BIOS would scream if it detected an unworkable CPU, but it didn't

well none of that came up but still i cannot start windows. it gives me the choice to "start windows normally", last known good configurations, safe mode and the rest. when i select any of them the computer just restarts!

is my CPU broken?


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## Tumbleweed36 (May 14, 2005)

Hi,

IMO......Two pins broken loose = Bad CPU


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## UncleMacro (Jan 26, 2005)

If you got lucky and only broke power/ground pins then your CPU can still work. There are lots of power/ground pins so you have a decent chance that those were the ones you broke. You might as well go ahead and find out. Did you replace your IC7-MAX3 with the same kind of motherboard or did you get a different one? If your new motherboard doesn't use the same chipset as your old motherboard (Intel 875), then you'll have to reinstall Windows. Windows installations usually won't boot if you change motherboard chipsets on it.


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## thinsitu (Dec 22, 2005)

well i've broken two pins right opposite the place with no pins, if you don't understand that please tell.

well i've re-instaleld windows and now it won't start up, i just see the start up screen appearing and suddenlly the computer restarts.

new mother board is an ASUS X seris socket 478.

btw- do you know if the socket 478 CPUs are still sold widely today? (not that i'm going to buy it in a month or so, i need to get some money first.:sad: )

well, it gets past boot stage nice and clean (although it beeps twice, maybe just a motherboard specific problem) but when it comes to starting windows i can see the startup-screen for half a second then the computer just restarts.

does it mean my CPU is broken (installing windows was fine), partially broken (is that even possible?) or totally broken?


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## thinsitu (Dec 22, 2005)

oh yeah btw do you have a map of what various different pins are on the CPU?


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## UncleMacro (Jan 26, 2005)

It'll take a bit of persistence but you can see which pins are broken with this datasheet. The diagram of the pins is on page 43. The two pins which are normally missing are A1 and B1 which are in the lower right-hand corner of that diagram. You can see what each pin does in the table which starts on page 52. The power supplies you can probably live without are VCC and VSS. If your broken pins are anything other than VCC or VSS then your CPU is broken.

You can still get plenty of socket 478 CPUs in the US. They're still pretty easy to get anywhere.


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## thinsitu (Dec 22, 2005)

hey, is Pentium 4 CPU temp 46-49C at idle and 56-58C at 100% usage high?

have a very merry chrismas and a happy new year everyone! (btw don't get drunk)


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## Tumbleweed36 (May 14, 2005)

Hi,

While the idle temps are quite high for idle and the under stress temps slightly high, they are within an operable range. Personally, I would never be satisified with those, but it won't harm your computer at those ranges. (btw: you are talking to someone who does not drink, so the drunk thing does not apply to me, but thanks for the thought)


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