Thanks MenthiX. I'm trying it now, so far it's found some empty sectors and two uncorrectable errors. Unless these errors aren't in files I can replace easily, it looks pretty good.
EDIT: i think it should also be mentioned that this drive has been through quite a lot, it's had a whole heap of data on it as what I suspect to be a backup drive, then I put XP on it a couple of times, and then ended up storing my files (about 25GB of mostly Doctor Who actually
). Its fitness according to SpeedFan wasn't all that great, but I didn't think it was that bad, it was only at about 75%.
EDIT2: Spinrite did it for me
I've now backed everything up to my laptop ready to be copied onto my new PC. I'm now formatting the drive, and I'm going to take it out and probably keep it in the aforementioned stockpile of odds and ends.
/ 
