hard lockup problem

For a while now, I have been having a problem with my computer crashing on me, not in blue screens, but in hard lockups. I have tried everything i can think of to figure out what the problem is, but i just cant figure it out. I have tried 3 different processors (Duron 800, Athlon XP1600+, and Athlon XP2000+) recently, all with the same problem. I have tried my hard drive in and out of RAID, to no avail. I have tried both of my RAM sticks together, and each one individually (2-256MB PC133), all 3 ways with the same results, but i havent gotten a chance to try somebody elses RAM yet. I havent tried a different video card, but I have tried several different Detonator drivers to try and fix it, as well as updated VIA 4-in-1 drivers for my motherboard. My processor stays under 45C when at full load also (currently using XP2000+), so overheating isnt an issue. My main thought, is that I have a bad power supply, which wouldnt surprise me after hearing some of the crap that happens with bad supplies. I have a generic 400W that I paid $27 for, which was never on the AMD recommended list for any processor (this was before i understood the value of a good PSU). I understand that without being here to try personally, this sort of thing is difficult to troubleshoot, but any thoughts on the matter would be greatly appreciated.

Thank you

Iwill KK266-R motherboard (BIOS updated to support XP processors)
Athlon XP2000+ (also used Duron 800 and XP1600+ with same issues)
2-256MB Crucial PC133 RAM
2 maxtor 40GB hard drives
Leadtek GeForce4 MX 440 64MB AGP
sound blaster live platinum 5.1
SK6 heatsink with delta 38
generic 400W PSU

Whats your 5v line at?
if its below 4.8 is almost for sure the psu.

Have you tried doing a fresh OS load on a newly formatted drive? Lockups can be caused by software, so don't automatically assume you have a hardware problem.

Sandra says that my 5V line is at 4.83V, 12V at 12.6, and 3.3V at 3.44.

And, I have tried it with multiple operating systems, 98SE, ME, XP, all after complete wipes, some in RAID, and some out of RAID or both ways, same problem.

Are you doing anything in particular or at a certain time this happens? Try clearing your BIOS. I find on most boards after installing a new CPU or new BIOS flash it needs to be cleared.

I have tried clearing my BIOS, yes. Also, it doesnt happen during anything in particular that i can tell at least, it crashes listening to music, playing games, watching videos, or reading a web page...absolutely anytime.

also, my 5V line is now 4.78 (was 4.83 a few hours ago, at least as reported by sandra), while the other 2 voltages have remained exactly where they were before.

Hmm... It might be voltage related. Try to run with only 1 Harddrive for a while and one stick of ram. It also sounds Hardware related so here comes the hard part of tearing apart the system and going piece by piece to make sure it's not the problem. It might also be the Motherboard, Did the computer ever work flawlessly?

Sounds to me like power is suspect...

Is there any pattern to the lockup? If it happens on a time of high CPU or graphics usage, then most likely it's power. Try to keep an eye on the power levels as you do things...you might see a drop on one of the lines that you don't see when you check things at idle.

Mike

The computer did work flawlessly until the beginning of last semester (around september 2002), when i turned on my computer one day, my NIC and mouse were both dead, and the instability started in bad from then on in. Im going to try running it with only one hard drive, optical drive, and one stick of RAM to see if that helps any, if not, i think i might be able to try a different motherboard from a computer at home. The lockups occur randomly, but never when the computer is sitting idle, I am always doing something when it crashes. Sometimes i will only have one IE window open and it crashes when i move the mouse a little bit, other times its in media player or AIM, there isnt a real pattern to it. I have been watching the voltage too, and the +5V line is the only one that changes, and it varies between 4.73 and 4.86.

Might wanna check the Capacitors around the board. It might be leaking. Also some motherboards that have suffered from USB equipement dieing might have the power controls on the MB for the USB damaged. This might also haved Damaged the PSU. I'm just saying this because i assume your old mouse was plugged in the USB port. Also sounds like the 5volt rail is damaged or the controls on the MB for the 5volt rail is damaged. Reason is because the NIC died b4 and PCI slots use 5volt rails.

checking the capacitors on the board was the first thing i did, I actually just replaced a motherboard for my uncle with 5 leaking capacitors on it. As far as the dead mouse, it was USB. The USB ports still work, and nothing else on them has been fried (yet). I just tried removing most components from the machine to see if that would help, like was suggested, and it crashed just as much with one hard drive, and one stick of RAM (in any of the 3 slots for it) as it did with all of the components in place. I noticed that the last few times it crashed, there were a few odd colored lines on the screen in random places, kind of like the monitor quit refreshing half way through a sweep or something, and just kept the odd lines in the wrong spot. I am going to try removing my PCI cards one by one, on the off chance that something is wrong with one of them, or the slot its in.

Thank you for all the suggestions so far.

Knock on wood, but i think i got it. One of my friends here recently upgraded his video card, and when i threw his old one in, i couldnt make the computer crash anymore (there were certain things that had been guaranteeing a crash within 10 seconds of starting). Now hopefully im not speaking too soon, but things are looking hopeful, in that i think all i will need to get is a new video card, and i have a GeForce2 to tide me over til i get it.

Thanks for everyone's input on the matter