Cannot Login

I've had no problem logging into the game, but now, whenever I open up the game, the login screen comes up, but then a few seconds later it turns completely wack! The screen glitches out, static appears on the screen, and it looks like your TV after something hits it too hard. Purple streaks, etc. The game is still running in the background though, and I can hear the music still, so it's not frozen, it's just the screen that's glitching out. When I tab out, everything is fine, but when I tab back in, same screen is glitched out. Funny though, when I screenshot it, it doesn't show the static, it shows the original login screen. It's weird, and infuriating. Any suggestions??? Thanks in advance!

Change the settings through the config file. All at lowest. First of all, try putting windowed.