Windows 7 has suddenly decided that when i hit fullscreen, fullscreen refers to only part of the screen (and aerosnap works the same way), and while i can pull windows into the unused bit, i can't have proper full screen (here's a video of what i'm experiencing). While i suspect rebooting will fix it, i'd like to know what exactly is the cause, and if there's a no-reboot way to fix it.
I'm running windows 7 32 bit, intel HD graphics 3000 (AKA sandy bridge) for graphics.

