MOUSE CURSOR STUCK IN AN INVISIBLE BOX! RESTRICTED MOVEMENT!!?

The range of movement that the in-game cursor can move in is limited to an invisible rectangular box inside the red line.
http://postimg.org/image/dkarsooup/
It seems like the cursor is stuck in lower resolution. What could be causing this?? And how to fix it? I've already tried run as admin, alt-tab, still doesn't work.