just a WAG. have you tried getting updated motherboard drivers?
I had a new system built with an amd xp 2500 atx mb barton motherboard 512mb ddr 400mhz memory with a geforce fx5200 128mb ddr 8x agp graphic card,and western digital 160gb caviar 7200 harddrive which was placed in a mid tower atx case 350w ps, and Window XP professional operating system. Since it was powered up and running it runs great for 30 min to 1hr then it begins to freeze and you cannot control alt delete you have to reboot the system. There is no specific place that it freezes and it is annoying can anyone help with suggestions to what might becausing this. the person who built it bailed on me when they could not fix it.
Frozen in time