Childers-
Personally, knowing what I know about computers, I think your story is a little off. I'm 27 years old, and have been working with computers since I was 7. (Do the math, that's 20 years. Nearly 2/3 of my life. [/smartass])
Now, I've built and rebuilt computers. I've used just about every piece of Microsoft software there is on the market. I have
NEVER had a message like you described, unless I inadvertantly entered the wrong product key. (However, with Operating Systems, entering the wrong product key will end up with you being unable to install the OS, not install the OS and give you a message later on. (Personally, five computers for less than $4500... *shrugs* Without knowing the stats of them, I can't say much, I guess)
However...I can offer this bit of information and advice, even though I'm personally inclined to say either a) you don't know a damned thing about computers or b) you're full of it: If the computers were everything he said they were (except for the "stolen" license,) go out and buy yourself a copy of WinXP. Format the computers, and install from the legal copy. Only pain is that you'll have to reinstall all the programs that were on there, which might require shelling out more money, unless he sent the software.
Eh... If you want, PM me and fill me in a little on the computers.
Spawn of Satan