Sorry Andrew, got absorbed elsewhere.
Yes Chkdsk will take a really long time, perhaps you should try growing the beans, picking them, roasting them before grinding and brewing?
Depending upon the size of the disk and the amount of data it could take 3 or more hours to complete.
It sounds like this is what you need to do, and to let it run.
Unreadable sector does not sound very encouraging, what make model disk is it?
Do you have it backed up?
If not back up then try checkdisk, if it is (as I believe it is) failing then the chkdsk may stress it beyond the pale..but it will have to be done..
NTFS, the filing system used by XP, is able to mark sectors bad and relocate recoverable data, but you need to run your disk makers health check utility.