Boot problems

Well, my extra machine took a surge the other day, and it has booted successfully since the surge. However, no matter what I do now, the boot to my OS will not complete successfully. I've tested the Power Supply and it checks out. What happens on boot is that I turn the computer on, and I see the Motherboard logo screen, it then attempts to boot and hangs right before the start up of the Operating System. I've tried these methods to get it to work:

I've reset the CMOS.
Checked the BIOS to ensure my HDD was being read by the CPU; it was.
Unplugged power cables and plugged them back in.

At the moment I'm trying to narrow down the hardware that isn't working so I can possibly replace it. I am also trying to reformat that computer as we speak(nothing of importance was on there anyway.) to see if that alleviates problems. Does anyone have any advice in the case that this doesn't work either? Perhaps I'm overlooking a simple troubleshooting method as I tend to do from time to time.

If the problem was software, the reformat should fix it. For future reference, there was probably no need to reformat - if the OS was WinXP you could have booted from the CD and repaired the current installation.

If the reformat doesn't work, it could be almost anything. Let us know how the reformat works out. We would need more info on what hardware and OS you're using.

You're correct. I've reformatted my harddrive and it seems to work fine again. I should have taken the opportunity to try and repair the operating system since i've never had to do that before. It would have been a good learning experience. At any rate, a new APC surge suppressor is on it's way and my backup computer will be back up soon.