Today when I was playing in multiplayer in Crysis 2 I wanted to press "ESC" button but accidentally pressed "tilde" which is under "esc". After that whole screen filled with "tilde" signs and i got huge lag and had to reboot my PC. After reboot i turned on Crysis again and also played multi, but after 1 minute my game lagged and on screen i saw only some weird colors like game changed into 8bit game. I rebooted PC again and had same situation again.
So my question is: How its possible that one button crashed my game?