BRUGGUSH'S PROFILE

So on my computer, on everyone's computer that I've encountered, my game works fine with Alt + Enter to fullscreen it. But on a friend's computer, Alt + Enter does NOT work to fullscreen the game, and neither does pressing F1 and launching in full screen. They want to stream the game but they can't get it to work in full screen. Even if the stream software isn't running. They've tried reinstalling it, updating drivers, closing out programs, restarting their computer. When they hold down Alt + Enter for a longer period of time it stops responding and freezes for a few seconds, but if they just hit it once nothing happens. Also, when they hold down alt and enter long enough it just moves on to the next message when i release the buttons. Their alt key works for everything else outside of the game so it isn't the Alt key itself that's causing the issue.

They have an NVidia 970 with a Sandy bridge I5 16gb Ram. They use a 46in Sony Bravia TV as their monitor.

If anyone could please shed some light on this, it would be greatly appreciated as it works for everyone except for them. Thank you!