Crashing when i try to start GMOD?

I just download the counter strike/GMOD package through steam.
Everytime I try to start gmod it says HL2 is not responding. Then forces me to close program.
I assume that means Half Life 2 or something. But I have counterstrike and I’m trying to load gmod. i don’t understand.

It runs on hl2.exe. CSS does too. Now could you post your computer specs?