For the longest time my system was stable. In July I felt it needed an upgrade. Originally I was running an Asus A7v26EE (might be off, dont have the box next to me) with a 1.1 AMD Duron, 512 DDR Ram, GeForce 5200 FX, and an ancient soundcard, and i upgraded to an AMD Athlon XP 2400, got a new case, and a 2nd 80 gig Seagate HD. Ever since then i've been getting strange lockups during gaming, where my character will continue running/jumping/casting/attacking, but the controls stop and the sound becomes softer and tinny sounding. after about 45 seconds of this it reboots, usually leaving me with a corrupted config.sys or some random file damaged. I've re-installed windows several times over the last few months because its been too much to fix. This afternoon my pc was sitting idle, then randomly restarted, and when it got to the windows log on screen, i got an error saying the file wasnt available, and to consult my windows installation disk.
 
Any ideas as to what my problem could be? I've kept all my drivers up to date, tested my memory, done a fresh install of windows, removed the old soundcard and started using my onboard sound, and kept an eye on my CPU temp.