Power outage, windows won’t boot

A few days ago I had my computer on and the power went out. The next day I turned my computer on, but Windows didn’t start up. The hard drive light came on and the fan came on, but Windows didn’t boot. (eMachines, running Windows XP with SP2)
I’ve been reading around and I think that it might be the power supply, but it’s just a guess…Here’s hoping that it didn’t damage my motherboard, if the PSU is the case… Is there a way to tell if that’s the problem? And is there a way to fix it, if it is the problem, or do I have to buy a new PSU?

Anyone else have any ideas of what it could be, other than the PSU?

Also, I found this: http://www.techspot.com/vb/topic62782-2.html
Mmm. Who else thinks I’m S.O.L…? =/