You could prolly just reinstall windows over the current installation and have it work ok.
First course of action though, should be a scandisk. Boot into safe mode, start it from there. If there are bad sectors, it may find them and move the info to a better location on the platter. If that is the case, I'd do a backup of all the info on the drive (personal files, stuff like that) onto another drive if possible. If not, to a cd would be fine. Then use Maxtor's utility to llf. That will write all zero's (i think, or it's ones) to the drive. From there you have to fdisk and partition it. Then format and reinstall windows.
After that it's just a matter of moving all your files back from the second hd or cdrom and reinstalling all the goodies.