Power cuts can be fatal and power surges / fluctuations which often happen just before a power cut can be even worse ... frying bits inside your PC by overloading them with voltage.
My first impression of this problem is that it sounds like your hard disk has suffered during the power cut. I assume that your PC was switched on when the power died?
Try starting up from a floppy disk (e.g. Windows ME Startup Disk), get to a command prompt and run
Scandisk /all
Does it report any errors or bad sectors?
If it reports errors but no bad sectors, run it again and again until it says it found nothing wrong. Then switch off the PC, boot off of the floppy disk again and do the same thing, just to be sure that there's
still no errors!
Let us know what happens as there will probably be more advice to give once that's been done
