Install the latest drivers for all your peripherals. You get these from the manufacturer's website.
If you still get random restarts or freezing, try this:
Boot the PC with only the most basic peripherals & use it like that for a while.
· hard drive
· video card (if not integrated)
If you don't get any errors, then start installing other hardware/drivers one item at a time. Play with the PC for a couple hours after each new hardware item (surf the net, view a video or two, restart the PC a couple times, etc...). If you don't get any errors, move to the next hardware item. If it freezes or restarts after installing something, then you've found your problem.
I still think the PSU is a possible problem though.
This post has been edited by Alex548: Aug 21 2009, 02:49 AM