I also have a problem in that I bought this G5 second hand and in the finder bit, under desktop there is a picture of a house and the old owners name. Can I change this to my name?
Cheers
Changing the short name might require going into NetInfo Manager or some other really arcane program. You could create a new admin account and delete the old one. (problem is, I've never figured out a way to delete de-activated accounts)