I was given an old pc which I wanted to fix up and donate. It's an AMD 600mhz slot A processor on a Gigabyte GA-71XE mobo with a Riva TNT2 vid card. I loaded WinXP and started to test things out. It will run all the MS system tools like defrag and disk cleanup. It also has no problem running some older kid's games and surfing the net, but when I try stressing the machine I have problems. Both Prime95 and 3DMark freeze the pc and when I try to run anything in Sandra the machine reboots. I tested the memory with memtest86 and it passed. Do I have a processor problem or is this stuff just too old... thanks...