Hi tiff27 and welcome to PC Pals,
Till a proper techie shows here, I may propose that you provide some more information about your PC and your OS.
Could be useful too to tell us if your problem started to appear after certain action from your side, like installing or uninstalling certain program, or any other event which happened.
I thought too of a possibility of (maybe) you've forgotten a floppy or a CD in one of the drives. If so, you can remove it first and restart.