This is probably the extreme end of the reason that I don't like performing work on a friend's PC. A friend of a friend is even more reason to stay away.

Not being a legal-type person, I've never heard of a cheque (yeah, we spell it differently down under) being a binding contract. The terms were never written down, so nothing would stand up in court.

Personally, I'd go over there and install the drivers just to shut him up. But then, I'm a big softie. Or you could take him to Judge Judy, if not only to watch her make a complete fool of him on national TV.