Garry's Mod Won't Open!

Every time I try to open Garry’s Mod it doesn’t work! first, I click on Garry’s Mod in steam and it looks like its loading. Then it says in the box ‘Preparing to Launch Garry’s Mod…’ After that goes away, it says down the bottom ‘Garry’s Mod’ with the little Garry’s Mod symbol bur after about 2 - 3 Seconds, It just dissapears and pretends nothing happens; therefore not opening Garry’s Mod.

I checked the system requirements many times and it is all fine. I also tried exiting steam, and opening it again more than one but yet nothing happened, and Its not only Garry’s Mod having this problem, it also happens with Counter Strike Source. The fact that my computer is a laptop might help to this issue but PLEASE HELP ME!

reinstall steam?

Happened to me when I picked a too high resolution. Try editing the config.cfg, find a line about the resolution and set it to 800 for x and 600 for y.

…where is config.cfg…is it in the …garrysmod/garrysmod folder somewhere?

I think theres a folder called “cfg” in there somewere