Computer issue

[Kope]

So I figured i'd get a consensus with everyone else before i go out and buy a piece of equipment I don't need.

Over the past month my computer has shut down 3 times while running EQ, randomly shuts off (but the computer seems to be partially powered on just not doing anything. I have to do a hard shutdown of the computer then reboot it to get it turned back on).

Last night my computer shut down and I couldn't get it running again. When I push the power button the lights flash, and fans go for about a second and then it all stops. During this time I've also seen a green light on my mobo flashing like power fluctuating.

I'm assuming this is my Power Supply. I'm concerned it might be my mobo or CPU though. Thoughts/ideas?