1366x768 Res isn't showing up as an option for me? I'm not entirely sure why.

I recently downloaded the newest version of the game, and added the patch by copy and pasting the files in and such. Ran in fullscreen at 1680x1050 Res. Everything worked fine but I couldn't turn right in game by moving my mouse to right. Whenever I tried, it would stopped at the edge of my PC's vis...