Check the capacitors on the motherboard...any of them look swollen, leaking, etc? Failing capacitors will cause random freezing, and will get worse as the caps fail. Just google "Bad Caps" for plenty of examples.
Ok guys, its not a software prob as it crashed on new install on new hd
i think i have found the answer, Although the ram testes completed and passed it seems to be the 4th GB in the 4th Socket. I installed each stick one by one until it fell over. On the 4th stick it froze again. removed the 4th stick and its been stress testing for about 1 hour and half now, just a waiting game now to see if it keeps it up.
Windows XP 32-bit does not support all of 4 GB RAM. Usually this does not cause a problem (the OS uses what it can, and that's it), but I wonder if it has something to do with the situation. Please keep us posted if the computer is doing okay without that 4th stick.
Just because Xp32 bit does not use the full 4GB ram, it can still access memory from across the 4 sticks of ram and going by the answer mentioned by arsenalbates I will say his 4th stick of ram is the cause of his problems.