Restart your PC.
It doesn't look like it'd close.
But this PC never restarts; I always puts it in stand-by because it's one of those great-running PC's that run great and take 40 minutes to boot up :c
Well if that is the only way.
I cannot alt-tab since the alt-tab menu shows up behind the TF2 window on monitor 1.
It just takes priority and I can't put anything infront of it.