I suggest you do a full format of the drive and reinstall your os. If you do not know how I can explain. The fastest, best way I use is run Killdisk to write the drive back to zero's. Free download in cd or floppy from
www.killdisk.com. Then according to which type drive you have, seagate, maxtor, western digital, use their version of Ontrack software to pre-format your drive using the largest partition available, takes only seconds compared to xp's or 98's format. Then when you boot up on your windows cd it can go directly to copying files!
Hope this helps.