Boot loop after BIOS screen

hi,
I have strange problem with my computer,after installing a game in the middle of the game say after 10-15 min it crash. On reboot, usually crash just after login, then still more slowly, or rather I can always go far without crashing. There I thought of a thermal problem (CPU card or screen). I have a P4 3GHz, 2GB Ram, ASUS P5GDC ave a PCIe EAX600XT and XP pro. Since yesterday, unable to boot. After the bios screen, a beep is it again, In Safe Mode, it goes to loading "Mup.sys" then beep ...

Thank you in advance.

I would say a chkdsk / P / R mode console on the boot cd of xp, a test of the memory.

hi,
I had run across this problem (mup.sys hang) on my desktop . I was able to get back into the computer by entering the Repair area after booting from the XP installation disk and running CHKDSK. That took several attempts.Then, CHKDSK ran very, very slowly. I then rebooted via SAFE MODE (again running very, very slowly), eventually making some repairs and getting past the problem. Ultimately, I had to change the power supply in order to return the computer to dependable operation, though the mup.sys problem never showed again. Was there an association between the mup.sys issue and the power supply or not? Who knows? My power supply was deteriorating, though I did not know it. It was very frustrating to pin down the bad power supply, as normally it would run everything just fine. However, as its failure progressed, it began to reveal itself at times of maximum power consumption. My suspicion is that the initial mup.sys issue surfaced when computer did not power down successfully due to a power
failure and a file (or files) was (were) left hanging.

My first thought is a RAM issue, but it is possibly a CPU or motherboard problem. I'm guessing you can't run memchk, is there any way you can try the ram on another computer?