The PC in question, using Windows XP Pro, only has one user. The previous user has left, a new user is now on the same PC. The log-in has changed to the new user, the old user has been removed. The new user has admin rights on the PC. The software is loaded on the PC. Files which the user works on are kept on a server over which the user does not have admin rights. I don't know if that covers your question.
Thanks for the response, though.