Garrys mod starts but is invisible

Hello, I am having an issue with my GarrysMod when I start the game it tries to launch but then it just shows a box in the top left of my screen and says, “GarrysMod” but it doesnt show my game it shows my desktop but when I move my mouse around I can hear the sound the buttons make when you hover over them, I have verified my integrety and reinstalled my game 3 times, and have even removed all addons and I just dont know what to do.

im having the same problem but im gay

[editline]18th September 2017[/editline]

im also transgender and my addons keep glitching out

[editline]18th September 2017[/editline]

but i also identify as an attack helicopter from now on so call me choppy and this problem is annoying

(User was permabanned for this post ("thanks for sharing" - postal))

follow this and use the -fullscreen command.

It sounds like the game isn’t launching in the correct resolution. There should also be a resolution option, which might help if you exclude the full screen command.