fullscreen problem

ok this isnt just cabal but any game i try to play. if it doesnt have a option in options that matches my resolution my computer no longer fullscreens it. it will go fullscreen but the game will be smaller too small to even read the letters and the rest of the screen is black

any fixes for this?

win xp sp3 ati x1950xtx
q6600 6gb ddr2 1022 ram