PC randomly shutting down during boot-up

[garymce]

Hi there, long time lurker and first time caller

A customer has recently shown me her computer which is having extreme problems booting up. The BIOS and POST both work fine, but it seems that anything beyond there, the computer will randomly shut down.

My first instict was faulty RAM, since I had that problem with my own PC a few years ago. I ran memtest86+ but it found no errors on either module. The PC has two 1GB DDR2 PC2-500 modules, I've also tried removing one, then the other and alternating between them but that hasn't worked either, so I'm assuming the RAM is fine unless it's a fault with the motherboard's connector.

My second check was removing the BIOS battery, starting the computer, then shutting it down and popping the battery back in to clear the CMOS but that didn't fix the shutdown issues either.

I tried running with just the bare minimum of PSU connections i.e. the 20pin/4pin and hard drive connectors, and again it failed to work. I removed the 300W PSU currently in the PC in case it was a power issue and replaced it with a spare 450W PSU I have, but again that didn't help.

It also doesn't seem to be a temperature issue as the heat of the processor seems to be remaining constant while in the BIOS monitor, although I have no way of checking while the PC is starting up beyond there but I'm assuming it's not the issue.

I've tried setting the BIOS to load both the fail-safe defaults and optimal defaults, neither of which have worked.

I also tried booting from a Ubuntu live disc to at least see if that was possible, but that also failed. The customer says that most days she can at least boot the PC to Windows Vista and can spend a random amount of time using her PC fine, then it'll randomly shut down and apparently after then it just keeps failing before even loading Vista. I haven't been able to reach Vista at all myself so I can't provide any information regarding that.

I'm absolutely stumped here. Any suggestions would be greatly appreciated!

Thanks
-Gary

 

[Lou Horton]

Since you said that most days it starts up and works for a period of time and then stops working I am still leaning towards something heat related.

Usually the bios temperature will stay steady because it is really not doing much processing. The real test of a potential heat issue is to check the temp in Windows while doing some processor intensive task. Playing a game, creating a movie, anything like this is a good test. I usually just use the system information (SIW) utility or speed fan to watch the temps in Windows.

Good luck!

 

[garymce]

The problem is, I haven't been able to get to Windows on it. I've only got the customer's account of that happening and thus I can't do any sort of temperature checks.

 

[NYJimbo]

.

It also doesn't seem to be a temperature issue as the heat of the processor seems to be remaining constant while in the BIOS monitor

What is that temperature (C or F). Don't expect much fluctuation while idling in the BIOS. I would excercise the cpu and the boot and see if its much higher.

Does the BIOS have any kind of heat warning/cpu health stuff ?

 

[DarDar]

I would check with the cust to see under what circumstances the pc will boot. Maybe she has a method or habit that seems to work. It could be a short or a bad solder joint somewhere that is causing the problem and they are a bugger to find.

Is it integrated or discrete graphics? I had a machine once where the graphics fan couldn't cope after a length of time.

Try running the full post and not the quick one to see if anything pops up.

Have a look for bad caps.

 

[garymce]

In the BIOS there is a PC Health Status menu, with the following:

Smart Fan Function: [Press Enter]
Shutdown Temperature: [Disabled]
Warning Temperature: [Disabled]

The following are grayed out:

CPU Tcontrol: 25*C
System Temperature: 28*C
CPU Fan Speed: 2156 RPM
System Fan Speed 0 RPM
CPU Vcore: 1.36V
VDIMM: 1.79V

Inside the Smart Fan Function menu the following options are available, all but the first are grayed out;

CPU Smart Fan Function: [Disabled]
x CPU FAN Low PWM: 0
x CPU FAN Temp of Low PWM(*C): 0
x CPU FAN Slope (PWM/*C): 0
x CPU SMART FAN Delta T: 0

 

[Rodel]

does it have an onboard vga? or separate one..try to check the vc...it sometimes cause the problems... God bless..

 

[garymce]

Yeah the graphics are onboard. I'll see if I have one lying around and try that, thanks.

 

[Rodel]

i hope it will work...you're welcome.....God bless...

 

[garymce]

Right, adding a dedicated graphics card didn't fix the problem

I also checked all the capacitors on the board and they all look fine, there's no swelling or leaks visible so I'm thinking they're fine.

The only other thing I can think of is taking the heatsink off the CPU and cleaning/reapplying the thermal paste and cleaning the heatsink and CPU fans out fully, I already cleaned the whole case with an air compressor but it won't hurt to check those parts fully.

If anyone has any other suggestions I'd be eternally grateful!

Thanks
-Gary

 

[Rodel]

have you tried to changing the ram? if you have another one...? not the one's used on that board...

 

[garymce]

Unfortuately I don't, I'm going to my local PC shop tomorrow so I'll buy a stick then to see if that makes the difference.

 

[Rodel]

if possible, just borrow from a friend... coz were not sure if the ram is defective...what's the pc specs?

 

[B Trevathan]

Since you are able to boot into the BIOS and stay in there for a while I don't think it is a heat problem or bad caps. I read you tried booting with just the bare minimums, PSU and hard drive, try this unplug everything again but this time also unplug the hard drive cable from the motherboard and unplug the power to the hard drive, because it could be a bad drive or cable, it should then give you a warning like no OS found or something like that.

 

[sjc@blainecs]

Not nit-picking here but kinda doing a summary

Dont think its the HD as he mentioned he tried booting with a Ubuntu CD and that did not work.

With a Boot CD there is only

- CD drive (not an issue I assume since not used during normal boot but unplug anyhow for next test)

- Memory - No tests yet. Can you pull one stick at a time or throw in any replacements even if they are 245MB? Or can you test the memory in another machine?

- PS - Already replaced/ tested

- Video - Already replaced/ tested

- MotherBoard - No ideas

Replace the mouse and keyboard with known good. And use differet slots, so if you have PS2 use USB. If you have USB then use PS2 or a different USB bus (I know this is a long shot and I have never seen this but being through)

Do you have an external CD-ROM to try and boot from?

Remove/ Unplug everything else. HD, CD-ROM (if you have external one) Sound cards ect.

Not a huge fan of BIOS upgrades but it might be worth a shot here (make sure you create a backup first) Or Reset the BIOS.

Just some random ideas, these are always tough to trouble-shoot and sometime we bite the bullet and try to find a cheap used MB for testing. I don't think this is a good idea but sometimes we have to know.

Good Luck and let us know if you find the issue

sjc
Blaine Computer Service

 

[garymce]

Memory - No tests yet. Can you pull one stick at a time or throw in any replacements even if they are 245MB? Or can you test the memory in another machine?

Tried that, same results Tried testing the RAM in my PC and didn't have any problems there either.

Replace the mouse and keyboard with known good. And use differet slots, so if you have PS2 use USB. If you have USB then use PS2 or a different USB bus (I know this is a long shot and I have never seen this but being through)

Didn't work either.

Do you have an external CD-ROM to try and boot from?

I do, I'll give that a try and see if it loads the LiveCD.

Remove/ Unplug everything else. HD, CD-ROM (if you have external one) Sound cards ect.

If I go with the basic "one stick of RAM, keyboard and monitor only" then it just sits there after POSTing saying "NVLoader", sits there indefinately with no problem.

Not a huge fan of BIOS upgrades but it might be worth a shot here (make sure you create a backup first) Or Reset the BIOS.

I was thinking of that also, I'll give that a try, thanks for the tips

 

[garymce]

Since you are able to boot into the BIOS and stay in there for a while I don't think it is a heat problem or bad caps. I read you tried booting with just the bare minimums, PSU and hard drive, try this unplug everything again but this time also unplug the hard drive cable from the motherboard and unplug the power to the hard drive, because it could be a bad drive or cable, it should then give you a warning like no OS found or something like that.

All I got was a message about NVLoader and then nothing else, so it seems to be an issue with activity, it can idle for as long as it likes it seems. It's baffling me to be honest, I can run memtest86 and Microscope 2000's hard drive tests from boot CDs fine, but attempting to load BartPE or Ubunutu's live disc or antyhing like that is a recipe for disaster.

In case it was a heating issue, I cleaned the CPU and heatsink and repasted it but that didn't help either.

 

[garymce]

Absolutely nothing seems to be working, I'm thinking the motherboard is goosed. Think I'll have to call it quits on this, thanks for all the help though everyone Much appreciated.