Crash on Server Entry

[Malefactor]

Downloaded and did everything and it worked fine, but set my options... Changed the Resolution and set it to full screen. When i set it to full screen it crashed. Have reinstalled 3 times. Unistalled, even deleted the bloody folder to put everything back to scratch. Reinstalled game, but it's still coming up as full screen (how i have no idea after fresh install and everything getting deleted). I can get to the server selection. When i click on it, screen goes black and brings up an error message. Something 0x0000015 and some other code. (that's not the exact message, but it's something along those lines). How do i fix it?