Display problems?

sometimes when i play games the game isnt covering the whole screen and some games it will , they used to cover the whole screen but now they arnt for example when i play payday 2 it fits to my whole screen and then i play crysis 2 its not covering the whole anyone got any solutions.

i have a 1080p moniter and a gigabyte 7970 graphics card

Have you tried going into display settings and switching to 1080p or messing around with some of he options to see if that helps?

yeah i haveĀ