I'm having problems with an old PC I want to set up in my folks house for internet use but am totally confused? it was starting up and going thru the motions saying it had not been shut down properly then jamming when loading XP now won't do any thing at all except show a black screen with the mouse pointer on it???

Does the BIOS POST run OK?

Try booting into Safe Mode by repeatedly tapping the F8 key after your BIOS POST but before Windows starts.

Do you have a retail XP CD or was XP pre installed (OEM)? If the latter do you have the recovery CD?