How to change name or administrator name in xp pc.

few days ago, i found a good pc at very good price with windows xp home. working very well, but de name of the former owner is all over. how can i delete that name and put everything in my name. am sure somebody knows about that. thank you.

 

thank you Tito: what i want is change the owner name in system, not in user accounts. i don't know if is the same, lets say when you install windows, you put your name and that computer is always in your name, right ? how you can change that. is possible ?