i used to have a customer/friend like this...
went through the whole win 95/98/mill/xp senario.
everytime a new operating system came out he wanted an upgrade usually trying foc. everytime he got charged and paid for extras as well.
the best one was a phone call at 1.00am saying it wasnt working and could he bring it back. (this particular time he had had it for nearly 5 months and no moans).
so he turns up at the house (much to my wifes annoyance) and i hook it up and its dead. he says he hasnt used it since he had it back as he was moving house (feasable just). when i open it up the graphics card is out of its slot and the power supply not plugged in. put them back to rights and everything hunky dorey.
as for not using it , he couldnt explain how i sent it back with a clean install, and all his works logs were there right up to that afternoon.
never been seen to this day.
or the best one, that i will never forget, i supplied a new build to one of my older customers, spent a lot of money on it . he said his son in law new a bit so would give him a few pointers and the grand kids wanted to be able to play on it.
anyway delivered it and set it all up, he even bought a new desk for it , but put it in the conservatory with no power sockets.
any way we got around that

and he was happy.
i came away thinking in true arnie style..I'LL BE BACK
met his wife in town 12 months later and gingerly asked how they were getting on , only to be told, the son in law didnt know anything , and they (wife and husband ) went on a computer course . ( they are both in there 80s) good on them i say.