Well, Trip, this is too little, too late, but I did run into the same problem as you just now.
How I solved it is alt tabbing back to Windows, and then right clicking on the game in the start bar, then selecting exit program. When I went back in, it told me that exiting would cause me to lose everything - proceed? I selected no, then hit F2 again. It worked at that time.
Hopefully you don't run into this issue again, but if you do, maybe this will help?