Hello! Sorry about your computer needing to be reset. That is definitely not fun at all.
Can you tell me which OS you are using, and what version? Also, are there any background apps running that display messages in-game, such as Steam or Skype?
Some programs are known to cause a crash on exit. The one that comes to mind is Plays.TV, but other software such as FRAPS can also cause the game to hang.
Sometimes holding alt after alt-tabbing and mousing over the windows' preview can help. You can often use that to "close" the program in the upper-right corner of its little window, with the little "x."
Let me know if any of that helps.