I was using the game in windows mode today for the first time and when I went to shut down the game the x in the upper corner of the main screen was greyed out.  I closed using the menu bar(right click mouse..get popup menu and close.) the next time I tried to play the game I got to the main screen but when i hit the play button i went back to desktop and nothing further happened.  When i rebooted it worked fine.  I tried using windows mode again to see if it was a one time thing and the same thing happened.  I thought you might like to know of this possible bug.
Tom D
I tried this on 3 separate computers with the same result
 
