I suppose the disk would be fine if they say so, but it's Seagate's program for Seagate's drive... Manufacturers don't like admitting their product is faulty.
If at all possible, run chkdsk /r
From what you've said, this seems unlikely.
If you have a floppy drive...
Run and follow the given instructions.
If all fails...
Download DBAN: http://www.dban.org/ppc.html
or another alternative for secure file deletion/formatting the drive.
Reinstall the OS!