See your other replies, and let me add the following:
If I acquired a used computer, no matter how I got it or who previously owned it, the
first thing I would do with it would be to reinstall the operating
system cleanly. You have no idea how the computer has been maintained,
what has been installed incorrectly, what is missing, what viruses and
spyware there may be, etc. I wouldn't want to live with somebody
else's mistakes and problems, possibility of kiddy p00rn, etc., and I
wouldn't recommend that anyone else do so either.
Your choice of course, but in my view, you're playing with fire if you
don't reinstall Windows cleanly.