Gmod doesn't work

I accidentally posted this thread in the regular forum, sorry if that was a no-no.
Anyway, when I load up Gmod, it boots fine, but when I load up a map, it doesn’t allow me to move or do anything except go back to the main menu. I tried deleting all my addons, but it still doesn’t work. Any suggestions?

Because your post was very broad (no error messages or anything) my only suggestion is re-installing the game.

Are you attempting to load a Lost Coast map by any chance?

No, I was trying every map, but it still didn’t work. I tried reinstalling, but still no dice. Any suggestions?

Have you replaced anything to do with movement / aiming? Sometimes movement and aiming mods can cause problems like this.