Hi, hope you can help. I've been having a problem for some time now where the pc reboots quite frequently (and randomly). I've tried a lot of things

1. Re-installed Windows XP Home on new Hard Drive (and downloaded all updates)
2. Installed Ubuntu standalone and dual boot (recently tried re-installing it and it crashed/rebooted during install)
3. Run memtest86 - found no errors
4. Reseated memory sticks
5. Tried both memory sticks (256Mb) standalone and in different slots
6. Tried a different memory stick (standalone)
7. Reset the BIOS to inital settings
8. Reduced the memory clock speed from SPD to HCLK

Once the PC reboots I have to leave it for a while before it will boot back into windows. I guess this implies overheating but it has crashed v. quickly after startup and quite a while after too. (I recently managed to get it to stay on all day with no problems). I've downloaded a CPU temp monitor and I've seen it crash with CPU temp at 40C & 53C - these seem to be temps in tolerance. Changing the RAM clock speed seemd to help for a while and PC stayed on for a good 18 hours - next day though it crashed after 1/2 hour and has been like this since even though I've reset the BIOS now.

I know you'll need some hardware specifics - can you let me know what you need. The motherboard is an MSI KT3 Ultra2 (MS-6380E). Has VIA VT8367 Apollo KT333. AMD Athlon 1500+ XP, 512MB RAM in 2 256MB chips. nVidia Graphics Card (GeForce Ti4200). Soundblaster Audigy

Thanks

Check for dust in the CPU fan.Also go into bios and find the shutdown temperature of the cpu and its current temp.

Hello Proj48,

It seems you have pretty much tried everything. The only thing I don't see in there is anything about the power supply. Considering your setup, I doubt you would need much wattage at all out of your power supply, so I doubt you are underpowering your computer. So that would basically make me think the only thing that is left is that the power supply is just bad.

The only other thing you can try that I can think of is testing it with a pre-install environment. Something like Bart PE or a live linux OS that runs right off of a CD. If you run one of those and don't see any rebooting, then that would show it is a software problem. But I very much doubt it is a software problem considering all you have done.

It really does sound like a hardware problem considering the total randomness of the rebooting. And I am also assuming it doesn't give you any blue screen or something since you seem thorough in your description and didn't mention an error message.

One thing you can do to test the power supply is go to a local retail store and purchase a power supply to test. If you install a good power supply and the problem occurs exactly the same way, then you can at least just remove it and get your money back. I would try two different power supplies before giving up on that idea because I have seen a good number of bad PSUs right out of the box.

Oh, one other thing you can try is removing all unnecessary periperal devices to see if any of those may be defective. Basically, get your computer to bare minimum. Remove modem, network card, video card, one stick of memory, etc. Of course only remove the video card if you have an onboard video port.

Hope that helps!

thanks Athlon - I've given everything a good clean with compressed air - its not shiny but not bad. All fans are working BTW. In the BIOS, the CPU critical temp was disabled - I've just tried setting it to 70C (and tried reducing the RAM clock speed again). But this still rebooted during Ubuntu install (I've tried to re-install as I wanted to eliminate Windows as the cause). Now I've got more problems, because its rebooting on the install, the Grub is corrupt so can't get into Windows! I guess that's the least of my problems right now!

thanks wadd - I'm not seeing any obvious power problems but I guess that doesn't mean much! I've not had a BSOD for ages (though I did get one when I mixed & matched RAM sticks but I guess i was asking for that). Wouldn't mind if I had BSOD - at least I might get some diagnostics! BTW the Ubuntu install is off a live CD (its not getting as far as actually installing the OS any more). I haven't tried taking out all the cards (bit nervous about putting them back in again) but I guess I've got nothing to lose now!

I think the writing's on the wall and its new PC time but I don't have the budget for it right now so trying to find of way of holding it together using sticking plaster until that lottery win comes along

Thanks

Sometimes the obvious eludes everybody, Windows creates temporary files each time you work on a file, creating it, or updating and resaving it. Many people not only do not defragment their disk by running Norton utilities monthly, (which will get rid of the unused space in between the files; your computer saves stuff on the hard drive but it doesn't do it in a nice orderly way, it puts it wherever it can, leaving gaps, these gaps are perceived by the system to be being used so your system thinks you have less space than you actually have. Norton will compress and consolidate the saved files getting rid of the blocks of unused space, freeing it up for any new stuff you save; it makes a difference). Also everybody needs to go to the C: drive, to their WINDOWS Folder, then to their TEMP or WINNT folder and see how many temporary files you have in there . The temporary files you need to get rid of have just numbers. These take up a lot of space and make your system run slow, crash when you open large programs, like Excel + anything else. In one month at my job I had more than 2,500 Temp files I needed to get rid of. To quickly get rid of them go to the first one, hold down the shift key, then scroll down to the last one you want to get rid of and while it is highlighted press the control key, you should see all those files highlighted, then hit your delete key and all the junk is gone. Just be careful only get rid of the number files. Do it in little blocks if you're not sure. Our computers are crashing a lot less now that we do this more often.

Have you had a look at your mainboard for leaking Caps this will cause this sort of random reboots problem to Blown, Burst and Leaking Motherboard Capacitors - A Serious Problem? - PCSTATS.com

If you have no leaking Caps I'd say its your power supply