Removing All Traces Of An User ?

Anyone know a good method of purging an XP pc of a user, like when a machine is sold and the new user wants all traces of the old user removed?

I thought I had a reasonably good method, which was to create a new user account, remove the default files from it's folder in Documents and Settings, copy most of the contents of the original user's folder into it, then delete the original user.

This method isn't too bad, and removes most of the obvious traces of the original owner, while leaving all the desktop and Windows settings intact.

But a scan with RegSeeker (incidentally, this is a damn good free app for finding and deleting multiple registry entries) revealed 85 instances of the old user name still in the Registry, so my method isn't 100% effective