|"I decided to take my chances of it being a SOFTWARE problem"|
"i'm being told this could be a motherboard problem"
"I also heard it could be CPU or PSU"
It's not a motherboard problem. Either your CPU is overheating or your power supply is overloaded. Start by checking the CPU temp in the BIOS.
I also see you list 6GB RAM & WinXP as your OS. Is that the 64-bit version of XP? If not, you have too much RAM.