Hmmm. Thanks for the information. Somehow I don't think I need a 500w PSU, especially since all I am running is 2.8GHZ, 7800GS, 2GB RAM, 2 optical drives, 1 hard drive, and that's pretty much it.

I am still unclear as to whether it's about the PSU or the cooling. So far it hasn't happened in the last two days (the shutting off randomly), so if I can avoid buying anything at all that would be ideal.