Hey,i have problem with Garry’s Mod when it loading multiplayer or singleplayer it just close (no crash only close) in processes is hl2.exe but it won’t work??? . Please if you know how to solve for this problem (Sorry for bad English)
Could be a problem with your video driver. You could try submitting a ticket to http://support.facepunchstudios.com/
Post specs of your computer using speccy and post a screenshot of what it shows. Would be faster not to submit a ticket as I would imagine they would be full of rust issues.
Update your drivers and get directx