Computer won’t boot- Help!

When I turn on my pc, the load screen appears and then the screen goes black with a blinking curser…I am running Windows XP. The power seems to be fine, so I tried to run the XP disk to fix the problem, and am able to get it to run the disk and go through setting up a repair on XP, but when it is finished, instead of having me complete the setup it reboots only to start the process over again. Help!