# Computer won't turn on..



## lsatblu (Jan 26, 2007)

Hi,

I have a custom build PC that has ran fine for about a year. Lately it has been getting really hot, well the graphic cards do. My friend said I needed a new power supply. I was silly and didn't listen. My PC now does not start up. I turn it on and it shuts off. I went out and got a new power supply, BFG 650 Watt. I put everything back into place as best as I could.

I plugged the PC in and turned it on. It turned on and then shut off. Apparently the PC does fully turn on when I do not have the ATX12V plug plugged in. When I turn the PC on without that plugged it, the PC turns on and runs, but I can not see anything on my monitor. 

I tried putting my old Power supply back and I have the same problem. It turns on fine when the ATX12V plug is not plugged in. As soon as I put it in, the PC shuts off.

Without the plug in, my monitor does not show anything and with the plug in, I don't get far enough to see if the monitor is working or not.

Any ideas?


----------



## dai (Jul 2, 2004)

if the old supply went it may have taken out the card see if a friend will try the card in their computer or if you can borrow another card to try in it


----------



## lsatblu (Jan 26, 2007)

What do you mean by card? Motherboard?

Sorry I am new at replacing computer parts.


----------



## dai (Jul 2, 2004)

video card
when you post you can only receive a reply to what you post
we rely on what you post to paint a picture of your computer,this is the only way we have an idea of what we are dealing with
what 
cpu
video card brand and model
when you power up what do the fans do when it stops
do they continue to turn or do they stop as well
when fitting the power supply you may have knocked the cpu heatsink,ram or video card


----------



## lsatblu (Jan 26, 2007)

dai said:


> video card
> when you post you can only receive a reply to what you post
> we rely on what you post to paint a picture of your computer,this is the only way we have an idea of what we are dealing with
> what
> ...


The motherboard is ASUS, two geforce 7600 graphic cards, the fans start running when I turn the PC on, but when the PC dies they do as well.

Everything looks like they are firmly in place and I had this problem before I took out the power supply.

It is strange because the PC turns on when the small ATX12V plug is not plugged in but the monitor does not connect like normal. When I have that plugged in, the computer and fans turn on and then shut off.

My friend said sometimes computers turn off to prevent themselves from destroying themselves or something, so I am not sure if the power supply is even the problem. I just hope it is because my computer gets really hot and I just got a new power supply for it.


----------



## dai (Jul 2, 2004)

will it stay on long enough to go into the bios and check the tempreture readings


----------



## lsatblu (Jan 26, 2007)

I'm unable to do that because I can't get that far.

When I have the ATX12V Plugged in, (It is a single wire that goes into my motherboard, I can take a picture to show you what I mean if you need) the computer starts up and turns off in two seconds. There isn't enough time for bios to run or anything on my monitor. It just turns on and shuts off.

When I don't have that plugged in, the PC turns on and runs. But nothing is displayed on my monitor even though it is plugged into the back of my computer like it always was.


----------



## dai (Jul 2, 2004)

the ATX12V should have 2 black and 2 yellow wires
do you get any bios beep codes
try a cmos reset
look at the new power supply and see if it has a setting for 115v and 230v
if it does check it is set on the right voltage for your country usa 115v europe 230v


----------



## lsatblu (Jan 26, 2007)

It actually has 4 black and 4 yellow but I am able to seperate the plug into two different plugs making them both 2 black and 2 yellow. Only one of them fits in the ATX12v slot though.

There is also no beep. It just turns on and then shuts off.

How do you do a cmos rest? I have never heard of it before.

I have it set for 115v because I live in USA.


----------



## dai (Jul 2, 2004)

turn the computer off
turn off at the power supply at the back
remove the lead
take the side off
remove the cmos battery
move the cmos jumper which is usually located alongside the cmos battery
from pins 1 and 2 to pins 2 and 3 and then back to pins 1 and 2
replace the battery and lead
turn on the power and try and boot
if no good
remove the power plugs to the drives just have 
cpu
video
ram 
speaker connected
try the boot again
if no good
try with only one video card in at a time


----------



## speedster123 (Oct 18, 2006)

What supply did you replace the burnt out one with?
Check the motherboard for any bulged or leaking caps.


----------



## lsatblu (Jan 26, 2007)

Hi,

I replaced the powersupply with a "BGD 650 WATT PowerSupply".

That should be enough power right? I'm not sure why my PC still shuts off right away though. My uncle said I might need to replace the motherboard now...Do you think that is the case?

The motherboard looks the same as it always has.

Edit: Also the light to the motherboard is on when plugged in. It is just strange how the PC turns on and then shuts off right away.


----------



## dai (Jul 2, 2004)

does it close down completely fans and all


----------



## lsatblu (Jan 26, 2007)

Yes, the fans turn on and then shut off with the computer.


----------



## dai (Jul 2, 2004)

set the m/b up out of the case with
cpu
video
ram
speaker
and see if it post
check both sides of the m/b for any signs of discolouration


----------



## speedster123 (Oct 18, 2006)

check the bench test in my sig as Dai suggested.
check that the heatsink/fan wasnt moved
even though the supply probably cost you $150 or abouts, it might be a bummer.


> try with only one video card in at a time


did you try this?


----------



## lsatblu (Jan 26, 2007)

Hi,

I have only one video card plugged in at the moment. I removed the motherboard from the case and set it up with just the powersupply, cpu, one video card, I attached the monitor to the video card and plugged just the power cord from my case onto the motherboard like the tutorial in your sig states.

I plugged the powersupply into the wall and turned it on. The light on my motherboard went on. I then pushed the button on my case to turn the PC on. The fan from the powersupply and cpu both started to rotate and then stopped compeletely. My monitor said no input recieved.

This is so confusing. It can't be the powersupply because this is a brand new one. I am not using my old one that I thought was causing the problem. The video card looks like it is in good shape and so does the motherboard.

What should I try next? Do you think I should go out and buy the same motherboard or something. I would hate to do that but at this point I just want my PC to run so I can play games again.


----------



## dai (Jul 2, 2004)

redo the paste on the cpu and try it
http://www.arcticsilver.com/arctic_silver_instructions.htm
if no good
remove the ram and see if you get far enough for the bios beeps it is missing
when bench testing remove the connections for the front case buttons from the m/b and start it by touching the 2 pins on the m/b with a small screwdriver for a fraction of a sec.


----------



## lsatblu (Jan 26, 2007)

I took out my cpu..and well it doesn't look like it did when I put it in there.



















I guess that can be just dust, but maybe it got too hot and thats ashes or something, I don't even see the AMD logo on it anymore..

Edit: I cleaned all that dust off. The computer now powers on and stays on. I connected the hard drive, video card and tried again. It still turns on but I see nothing on the screen..

I remembered that I need to plug that ATX12V plug in...I did so. The PC turns on, fans and all and then shuts off in two seconds. There is no time for anything to even appear on the monitor.

Thoughts?


----------



## dai (Jul 2, 2004)

did you bench test
check you have no swollen or leaking capacitors


----------



## lsatblu (Jan 26, 2007)

Not sure if I can fully do a bench test. I have my computer parts all on my desk. The motherboard is connected to the powersupply, one video card and the monitor. It turns on and the fans run.

When I put the ATX12V plug in, the fans stop right away and it shuts off. I never even get close enough to see the bios screen or anything. Nothing ever appears on the monitor.

I don't see anything out of the ordinary on the motherboard, it looks pretty much how it always did..


----------



## dai (Jul 2, 2004)

it looks like a dead short somewhere
with the aux 12v lead out and the ram out do you receive any bios beeps


----------



## lsatblu (Jan 26, 2007)

My roommate said something similar. With the ATX12V out and no RAM, basically everything is disconnected. I don't get any beeps. I am trying this with just the powersupply connected to the motherboard and cpu. The fans turn and the motherboard lights up, but no beeps.

The same happens once I put in the video card, hard drive, ram and monitor on. They all run but nothing appears on the monitor. Once I put that annoying ATX12V plug in, the computer turns on and shuts off.

I never hear any beeps.

Maybe the ATX12V is shot? I hope it is just the motherboard that would need replacing and not the CPU as well. The CPU should be fine right? The Asus fan connected to the CPU spins like normal. I think its just the motherboard..


----------



## dai (Jul 2, 2004)

i would think it's the m/b


----------



## lsatblu (Jan 26, 2007)

Hi all,

I replaced the motherboard, and redid the paste on the CPU with that Arctic Silver 5 stuff. The computer starts up fine!

The only problem I have had so far is when I am playing Oblivion (pc game). It seems to freze afer a few minutes of playing. I wouldn't think this would happen because I have two pretty powerful graphic cards, a new motherboard, new powersupply and I redid the paste on the CPU. 

I'm going to ask on the Oblivion forums about this. Thanks for all the help!


----------



## dai (Jul 2, 2004)

does the psu put out enough power to run the system when it's under load


----------



## lsatblu (Jan 26, 2007)

I'm not sure...the graphic cards don't get burning hot like they used to. How would I check?

I actually do have another problem...the computer is only recognizing one graphic card even though I have both plugged in. I also have the latest drivers for nvidia installed but there is no option for SLI. I have both cards installed and I have the bridge thing connecting them...its really strange. I removed both and added them again but the computer doesnt seem to realize that.


----------



## dai (Jul 2, 2004)

can you try the one that's not working in another computer to see if you have lost it


----------



## lsatblu (Jan 26, 2007)

Really strange..I removed the video card in the first slot and put the second card in its place. I started the computer and the card works. I then put the card that was originally in first place, in second place and turned the computer on. It automatically found the card and enabled SLI. 

The cards are getting pretty hot though. I actually have the side of my case off and a fan constantly blowing on the computer to cool it down. Is that okay? I have a small fan on the inside but it doesn't do much. I think/hope the power supply is enough. I just spent so much money on it. My old powersupply was a really low wattage and the computer ran on it for a year. My new one is 650wats. That should be powerful enough, right?

I still get that message wanting me to install a new multimedia device but I have no idea of what it is or what cd to put in to install it..

Edit: The cards don't seem to be getting nearly as hot with my fan blowing on them.


----------



## dai (Jul 2, 2004)

you need a fan on the front intakeing cool air and one at the rear exhausting the hot air
this creates a flow from front to rear across everything
check the temps of the cards,this usually lists them
http://www.cpuid.com/pcwizard.php
with power supplies you get what you pay for a quality 450 will out perform a low quality 650
check the device manager and see if there is any yellow alongside of anything it may indicate what it is trying to install


----------

