# [SOLVED] Power but no post, no boot (sometimes)



## dr.garbanzo (Aug 10, 2009)

System is a prebuilt, no-name, about 9 months old:


```
micro-star ms-7529 MB
core 2 duo e7200, 2.53 ghz
2x ddr2 pc5300 1gb, 667 mhz
geforce 9500gt, 512mb
one SATA hard drive
one SATA optical drive
no other cards or anything inside
```
My problem started three days ago. I press the power button on my rig, and the boot process does not initiate. The PSU fan spins up, the hard drive read light flashes a few times, and the optical drive read light flashes a few times. Then it just hangs. I can open/close my optical drive at this point, but capslock/numlock/etc do not work. The monitor is receiving a signal, but there's nothing to display.

Pressing reset a few times will finally get things to kick on. I know it's about to boot when the lights on my keyboard flash. Once it boots, it runs all day without issue.

I first opened the case, gave it a good dusting, and re-seated RAM/video card. No help.

Then I removed my RAM entirely and turned it on to hear a continuous beep which, according to what I read, suggests the motherboard is OK (?)

I replaced one RAM, and it wouldn't boot. I switched it for my second, and it booted. I tried the process again to be sure - same results.

Content, I put aside the "bad" RAM and went on with my day.

This morning, it didn't boot again with the "good" RAM, so i but the other one back in, went through pressing the reset button several times, and managed to boot.

Not sure where to go from here. This is my only machine making it hard to swap parts. I have access to some old PSUs at work, but have never switched one out...

Any thoughts? Suggestions?

Many thanks!


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## koala (Mar 27, 2005)

*Re: Power but no post, no boot (sometimes)*

Hi, welcome to TSF

I had this problem on an old Asus motherboard with Kingston RAM. Never managed to fix it though. I ended up replacing the board and RAM. My workaround was to clear the CMOS and reboot. On the second or third attempt it would boot properly.

Do you get any error messages during POST? Anything about the CMOS Checksum?

Have you changed anything from default in BIOS?

What make/model and total watts is your PSU?

Are the RAM sticks a matching pair?

Test your RAM one stick at a time using a Memtest CD. Obviously, this might not work first time, so keep trying for each stick until it boots into memtest.

Direct link to pre-compiled bootable ISO: *http://www.memtest.org/download/2.01/memtest86+-2.01.iso.zip*

Unzip the file and burn the ISO to CD (as an image, not as data) to create a bootable CD. *SAB Burner* is free and very easy to use, just click the BIN/ISO icon to burn. Reboot and go into the BIOS. Change the boot order to 'CD first', save settings, insert the CD and reboot. This will start the program. Run for one stick at a time (very important, to prevent false readings) for at least 10 passes each.


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## dr.garbanzo (Aug 10, 2009)

*Re: Power but no post, no boot (sometimes)*

Many thanks for the reply!

When it finally does boot, I get no errors during post.

No changes made to BIOS recently.

Not sure about PSU, I'm at work now. I'll have to check this evening.

RAM sticks are identical.

I'll also run that RAM test when i get home. Though this morning I ran the new Memory Diagonostic Tool that's built into Windows 7 and found no errors...


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## dr.garbanzo (Aug 10, 2009)

*Re: Power but no post, no boot (sometimes)*

ok, i must have hit Reset 50 times today just to get this thing to come out of hybernation. i don't want to restart to try the memory check! i've tried both chips in every possible configuration - unless they're both failing, i really don't think that's my problem.

today i took it all apart, every little piece, and cleaned it all with canned air. i put it back and tried with the bare essentials - hdd and integrated graphics, plus keyboard and monitor - still no post.

anyway i finally managed to boot, and according to HWMonitor, all my voltages look ok...

so, the questions is this - do i buy a new PSU, or a new motherboard?


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## Tumbleweed36 (May 14, 2005)

*Re: Power but no post, no boot (sometimes)*

What is the brand name and wattage of the power supply presently in there and how long have you had it?


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## dr.garbanzo (Aug 10, 2009)

*Re: Power but no post, no boot (sometimes)*

the current PSU is a Mercury MKP-4400, 400 Watts.

the entire system is about 9 months old.


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## Tumbleweed36 (May 14, 2005)

*Re: Power but no post, no boot (sometimes)*

A mercury power supply does not have enough amps on the +12 rail to run a pci-e video card successfully for very long. This is a very weak model and similar to the dynex models. Do you know anyone who has a good 500 watt power supplly to try in your machine.


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## dr.garbanzo (Aug 10, 2009)

*Re: Power but no post, no boot (sometimes)*

no, i really don't. 

if i were to go out and buy one, what should i look for?

would a failing psu give me problems booting, but once i've got windows running, let me run it for several hours straight, playing fps games and watching 1080p movies? because that's what i did last night when it finally booted...


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## Tumbleweed36 (May 14, 2005)

*Re: Power but no post, no boot (sometimes)*

First of all, if the power supply is not up to the job, yes, that would fix those issues and it certainly looks that way to me. If you are going to purchase a power supply, you need at least a 500 watt power supply to run that card. Here is where you should be in power as a minimum IMHO:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817151034

/or/ (larger at the same price which will let you upgrade the video card in the future)

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139005


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## dr.garbanzo (Aug 10, 2009)

*Re: Power but no post, no boot (sometimes)*

hmmm. 10% of my monthly salary seems like a lot of money to spend on a solution that _might _work...

anyway i'm in europe, i can't shop at newegg...

it seems that everyone i ask has different opinions. some say that advertised wattage means very little, and that a high quality psu with lower wattage is plenty to power a basic system like mine. others say the opposite. even various calculators i've tried online suggest 300-400 for my system...

but i'll see what i can get. i wrote down the trusted/untrusted brands in the sticky, and i'll go out shopping after work...

:sigh:


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## koala (Mar 27, 2005)

*Re: Power but no post, no boot (sometimes)*

If you don't want to spend your money on a new PSU, you could take it to a PC repair store and get them to test all the components. If they know what they're doing, they'll tell you that your PSU is not suitable for a PCIE card.

As it's only 9 months old, is it still under warranty?

The total wattage of the PSU is not as important as the +12V amps when it comes to powering the graphics card, CPU and hard drive. It's the +12V line that bears the brunt of the workload under stress, so it needs to be sufficient.

The Mercury MKP-4400 PSU only has 19A on the +12V line. This is enough to power an AGP card or onboard graphics, but PCIE cards need a minimum of 28A. Anything less than this will cause the unit's power output to deteriorate over time, possibly damaging other components as well.


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## dr.garbanzo (Aug 10, 2009)

*Re: Power but no post, no boot (sometimes)*

thanks for the reply. i'm not trying to be stubborn here. i clearly don't know what i'm doing. but i guess the people who build this computer didn't either...

a few hours ago i ordered a coolermaster m520. will that also be insufficient? it's 19A on the +12, but there are 3 of them...

as for warranty - i killed it when i opened the case to troubleshoot. i live hours away from where i bought it, and here in hungary, they'd just find a reason not to follow through anyway...


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## koala (Mar 27, 2005)

*Re: Power but no post, no boot (sometimes)*

It's ok, I know you're not trying to be stubborn and you're just looking for cheaper ways to fix the problem than buying a new PSU. I'd be the same in your position. :smile:

The 520W Coolermaster will be ok. When a PSU has more than one +12V line, you combine the amps on the lines and then take 80% of that total, so 3 x 19A x 80% = 45A, plenty for your system.

There's a possibility that the weak PSU might have damaged your other components, so you might want to have it fully tested if the problem occurs again.


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## dr.garbanzo (Aug 10, 2009)

*Re: Power but no post, no boot (sometimes)*

could i harm components by running it on my old psu?


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## koala (Mar 27, 2005)

*Re: Power but no post, no boot (sometimes)*

If they're not receiving enough power when stressed (fullscreen games, videos, etc), they can overheat. The damage might not be immediately noticeable, but could appear a few months down the line, as seems to have happened with your PSU.


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## dr.garbanzo (Aug 10, 2009)

*Re: Power but no post, no boot (sometimes)*

ok i'll keep an eye on temps. new psu should be here friday.

thanks for the help.


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## dr.garbanzo (Aug 10, 2009)

*Re: Power but no post, no boot (sometimes)*

well... it's not the PSU. i just put in a brand new one and the problem persists.

1. press the power button
2. hdd light flashes once
3. dvd light flashes several times
4. nothing

a few days ago, i could get it to boot after pressing reset several times. i knew when it was about to boot because the lights on my keyboard would flash, and the power light on my monitor would turn from orange to blue. then it would post/boot. but i'ts not been up for a few days...

cpu and gpu fans run
ethernet light in the back flashes
but no power through usb...

where from here? i guess it's the motherboard? maybe i should just bite the bullet and take it in someplace... i can't afford to keep playing 'guess the faulty component' Smile


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## dr.garbanzo (Aug 10, 2009)

*Re: Power but no post, no boot (sometimes)*

it was the motherboard...

thanks to all who helped!


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## koala (Mar 27, 2005)

*Re: Power but no post, no boot (sometimes)*

Thanks for posting your solution. Now you have a better quality PSU and new motherboard, you should be ok. I'll mark this thread as solved, but post back if the problem returns.


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