Freezing issues

I just built my first system and It runs great then some times in CS source / HL2 it will just freeze. Americas Army either freezes or gives me an error message. After this happens I felt my components and they did not feel very hot. Sometimes it just restarts and windows says it just recovered from a serious error. It never freezes just running.
3200 venice
500w fortron
2gb ocz value vx
x800xl

Sounds like it may be an issue with Windows. Try removing/reinstalling your games and give it another go. Or, shut down some non-essential processes using the task manager and try again.

Also check your Video drivers are up to date, and windows is properly identifing your card.