http://forum.toribash.com/showthread.php?t=460082
^ If you don't read yet, try it
And i think is your graphic card drivers
Did you recently install a windows update? Because sometimes the drivers of the update aren't the right for your graphics card.
If you're graphic drivers are already up to date (from the official website), I suggest to use an earlier driver to test if it changes something.
Is it only ingame or do you have the same problem with the menu?