Garry's Mod closing when doing things

My garry’s mod has been doing this for a while, and i just want to play. My game will work fine until, i have to do something like open console or pause the game and it will just close. I run it at -dxlevel80 because of this previous problem i had and it fixed that. If anyone could help, it would be greatly appreciated.

post specs

also dx80 is no longer useable, you should use dx8.1 instead