my cuz had borrowed a legit halflife cd original. from some one at school, and installed it, and used a real halflife code that came with that copy, and installed team fortress DL. Now she's got the cs pack from staples, and she tried to install the cs cd. then it said the executable was corrupt. so she tried removing all the old Half life junk and installing just the new cs, and that's not working. and she tried installing the original halflife again.