Judging from the sounds of it and my many many many many harddrive failures, I'd say you might need it.

The error itself (DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRES ENTER) might mean you have a corrupt file partition or something like that. Anyways, are you sure that you can't access/do any diagnostics on your harddrive at all? If you can I guess you might want to see what Hard Drive Diagnostics says under XP which should be under Boot Setup which is F12 on my comp.