Have you done a drive test to see how many bad sectors there are? If it's clicking away consistently (ie, choking on more than one or two bad sectors) then you may not even have much left to save.
Try Seagate Seatools:
http://www.seagate.com/www/en-us/sup...oads/seatools/
Download the ISO and burn it to a CD (make sure you burn it in ISO mode, don't just copy the file to the CD). Do a drive short test (DST) then if that succeeds a longer one. Also check to see if SMART has tripped.
BTW, this will test any brand drive although there are some extra features available for Seagates.