Ok, so I now added the folder to the exclusions and it was working right, until I opened it and clicked in Singleplayer. This closed the game and said "Some Ddl files are missing. Please reinstall." And well, that's it. I'm running this on Windows 10, if that matters.
Installed a patch and fixed it. (Karspersky did delete something but well, at least I can open campaign). Now, when I click in Singleplayer a big window is opened and a error message says "This product requires a 16bit pixel depth" and closes again.
EDITING (once more...): I found that the problem was the Windowed option. It made the pixel error appear. Now I'm dealing with another one (how strange..). It basically makes the game like freeze when I'm moving my mouse. The mouse appears and dissapears everytime I move it too.
EDITING #2: YES GUYS, FINALLY, IN THE THIRD EDITING I CAN CONFIRM I SOLVED IT :___). I just changed the renderer to something random (TSS) and it was fixed. Thanks to the admins that answered in another posts like this. They helped me get this solved ^__^