Retrace your recent steps. Have you changed any settings or messed around in the config files? Have you updated your drivers? Have you changed any other PC settings that are unrelated to gmod. There are a lot of factors that could be causing issues. A good way to start would be by removing all addons and re-installing the game.

Retrace your recent steps. Have you changed any settings or messed around in the config files? Have you updated your drivers? Have you changed any other PC settings that are unrelated to gmod. There are a lot of factors that could be causing issues. A good way to start would be by removing all addons and re-installing the game.