Thanks Fruit Bat, totally forgot about the discrepancy caused by our "rounded" mathematics!
HondaMan, I've read a few of those "Toms Harware" articles, but that one is not relevant to my problem.
The XP PC that this disk was originally in has long since gone to the bone yard!
The disk still had all the partitions and files etc on it.
I have just wiped the info and now have an empty disk with just one volume.
The disk is in a caddy attached to my current PC via USB 2.0 and I wanted to format it NTFS so that I can use it as external storage.