I have owned my current computer for a little over a year, now, and have been having some intermittent problems. After I first got it, during certain games (not all games, just some), it would randomly either reboot, not display anything (but still play sound), or exit and display a message saying that my video card had stopped responding. This made it seem like a video problem. I tried some different things, none of which worked, and ignored it for a while and stopped playing those games. That worked for a while, but I wanted it fixed. The cheap PSU that came with the case fried, so when I bought a new PSU, I also flashed the BIOS so I could get my SATA drive to work. (that's a different story, though) Suddenly, it worked. No more random resets... for a while. Recently, I got Neverwinter Nights and Battle For Middle Earth II, and now, on 4 occasions (in less than 2 weeks) had both reboots and "card not responding" errors. I've done some research, and found that the Abit AX8 motherboard that I'm using is a little flaky with its stability. What I'm looking for are ideas to fix the problems without requiring new parts, if possible. I'm going to spend some money on upgrades before next year, but I'd really like to not have to spend it now. I doubt it's an overheating problem. Possible, but unlikely. I once ran my computer with the side panel off and a box fan in its place, and it still happened. Anyways, system specs are: Abit AX8 revision 1.0 motherboard (socket 939) Abit X600 XT video card (I got an insane deal on mobo and video card, if you're wondering) 3x 512 MB Corsair DDR400 Athlon 64 3200+, Venice core I guess most of what I've learned with this first build of mine is that you get what you pay for. I'm definitely going with an ASUS motherboard instead of Abit next time. Any help would be very much appreciated! No, it isn't fork. I checked.

Not sure if this will help but...

Do you have the latest drivers.

Also install the Catalyst Control Center and it'll give you the temps for your card (under Overdrive). I think for the X600XT, it should idle in the 40s and not hit more than 70 under load.

Drivers? For video, I update monthly.

For the rest of the system, that's a really, really, good (and blindingly obvious) idea.

control pannel -> system -> advanced -> startup and error reporting
From there you can uncheck the "reboot" checkbox to keep it from rebooting on you. This means that you
will get BOSDs in their place, but atleast then you can diagnose what is causing the problem.

Well, you mentioned that you already replaced the power supply. That would have been my first guess. Just out of curiosity, how big is your power supply?

It's here.

It's 430 W, but I don't really need more for my rig. It looked great for the price, and performs very well (and quietly).

Well, I updated motherboard drivers, disabled "reboot on critical failure", and it still happened.

Not 12 minutes into a game of Battle For Middle Earth II to test, and I stop hearing audio, my monitor displays its input not found screen, but my computer still has power. The fans and all are still spinning. I try Ctrl-Alt-Del, moving the mouse, clicking, and it gives me a long beep from the motherboard. I'm going to look up the beep codes for my board and see what I can find.

Sounds to me like something could be overheating, or maybe one of your RAM sticks is broke.

Try each ram stick on its own and see what happens.

In my case, I owned a GeForce MX 4000 and experienced similar problems. It was the video card's failure. Now I can't even boot when I plug the card in.
As the video card was not working right, different drivers managed the hang ups differently. Stopping having video signal was one of my problems.
Also blue splash screens blaming the video card/video drivers appeared too.
Everything can happen when drivers (or worse, the video card) are not working right. Overheating is also very common. Try (if you can) underclocking your card.

Good luck!
Dark Sylinc

PS: However, my integrated SiS 741, does the same blue splash screens because the drivers have some bugs, but they usually weren't random, as I could isolate them (the video card is not good when rendering in wireframe mode, for example). So may be those games are not compatible with your video card....
Try downloading some samples (i.e. the DirectX 9.0c SDK samples) and running them intensively. If you see that your PC freezes with certaing samples, research what special feature do that sample use (it is driver fault), and if they hang up after a period of time... it is an overheating problem

Checked my temps multiple times, nothing overheating. I ran 3Dmark for a while, and video temp was fine. I doubt it's a RAM problem, but I'll try memtest86 soon, if not just pulling out random sticks to test.

Thanks for the ideas so far!