About a week before Christmas there was a power cut in my area. The PC was running fine at the time. A few hours later when power resumed I powered up my PC and it proceeded to stick on the "Starting Windows" screen.
I tried startup repair. It would just run and run and run with no progress. I've tried booting in safe mode etc and nothing. I done some searching and I get the impression that my drive is screwed.
Any help would be appreciated, especially on how to proceed if the drive does need replacing.
It would be unusual for a hard drive to be "screwed" by a power-cut alone, though data corruption would not be unusual in those circumstances, such that Windows won't start in any mode.
You first need to test the drive with the manufacturer's diagnostic software which loads from a bootable CD, before buying a new one. The links for the manufacturer's diagnostic software are here: http://www.tacktech.com/display.cfm?ttid=287
If you have another computer, or an extra power supply, try replacing the power supply. I've seen many power supplies damaged in the past from power failures. I've seen computers actually boot up fine and then after several minutes they reboot for no reason. An unstable power supply damaged from a surge or brownout can cause a hard drive not to function properly. If you don't have an extra power supply, but have another computer, take the hard drive out of the non-functioning computer and boot it up in the working computer in safe mode and see if the problem goes away.