It could have been worse. You're lucky you got the laptop back at all. You should check to see if the copy of Windows 7 is genuine. In the future. avoid sending anything to people on Craigslist. Most cities of any size usually have a few Mom and Pop computer repair shops that have been in the same location for years. They would be a better bet.
Also, with a little bit of reading, watching videos and asking questions on the forums, you can usually solve the issues without having to send it anywhere.