Also, check that the game doesn't run into an infinite loop the moment it starts (if this happens before the first draw event, the window might not even pop up even though the game is running). Even finite loops can give this behavior if they're long enough (like looping over 10 million entries instead of 100 because you added too many zeroes somewhere without realizing). It's hard to tell if your game is in an infinite loop, but opening Task Manager to see if the runner executable is using lots of CPU power is a quick and easy way.