BOAC, you've got some talking to do. Mixture has nailed it. Try to explain to him that pulling out a 10yr old PC and trying to do anything satisfactorily with it in todays world, is the equivalent of him trying to tootle down the M1 to London in a Model T.
It won't cut the mustard - neither in performance, nor in OS - and it really is a waste of time trying to teach the operation of a 10yr old PC & OS, to a non-computer-literate person.
Buy him a current piece of kit - the stuff has never been so cheap, and current performance and AV protection is so far advanced over 10yr-old technology, it really doesn't warrant comparison.