I can´t see the game when i start it, only hear it

[TioLucian]

I need help please, when i first installed the game, i changed some advanced settings in the t6 zombie mode, like resolution and stuff, but when i tried to aplied it, the game kinda crushed, and now, when i launch the game, i can only hear it but i see my desktop. i unistalled and reinstalled the game several times, but i have the same problem over and over. btw the problem only happens with the zombie mode, not the multiplayer.

[HannesC]

Type r_fullscreen 0; vid_restart into the bootstrapper cmd window and try getting into the game again.