Pretty much any hard drive that uses the same bus will be fine. If you have a IDE drive then any IDE or PATA drive will be fine. If you have a SATA drive then any SATA drive will be fine.
It should say on the docs that came with the computer what bus it uses.
A 2002 model will use an IDE drive. Open the case, you will see a flat grey ribbon atached to the hard drive. This is IDE. Any IDE drive should work.