Garry's Mod wont start/load

Hey guys, I recently downloaded everything again, and i ran some source games. When i tried to start Garry’s Mod it opened the window and did not respond. I waited an hour and it did nothing. Any ideas? I tried validating.

Specs:
i7 920 @ 4.2 GHz
2x EVGA GTX 275s
6GB DDR3-1600MHz CAS8 RAM

Have you tried restarting your computer?

>:[
thats what everybody says. No it wont fix it.

I’ve already restarted.

Have you tried cleaning your Gmod folder? (if you downloaded addons)

no i just downloaded it, fresh and new.