Umm basically my gmod crashes whenever i get to the loading screen with gman and the cone on his head. Ive tried reinstalling it. I tried renaming the folder like Si said but everytime i do that it creates a new one with the original name and uses that one and crashes.
Any ideas?

Have you done anything recently such as updating graphics drivers?

Can you run it in some sort of compatability mode?

-autoconfig

Use it

He's done it now, cant remeber what it was but he found the answer on youtube of all place