I tried to change my graphic settings and now I am unable to see the mw3 screen.

[Touny]

I saw in a previous forum that someone suggested eliminating the "player" folder and that that would fix the problem. the issue is that I have no idea where to find that "player" folder

[Resxt]

Make sure your game is closed before doing that.
Go in this folder %localappdata%\Plutonium\storage\iw5\players.
Then open config_mp.cfg with the notepad to edit it.
Find r_displayMode and change it to be like this (you can use ctrl+f to search for it):
seta r_displayMode "windowed (no border)"