Gmod Univaliable

I have tried to play gmod for the past 4 days and it keeps coming up with this popup, whats wrong?

Restart steam, try again. Problem shouldn’t persist.

Im sort of a Newbie, to steam, how can I restart it?

I’d suggest logging out, going to C:\program files\steam and delete clientregistery.blob, and log back in.

The problems in the steam folder itself.
Just delete c:\Program Files\steam
Try deleting steam.exe, clientregistry.blob and even steamapps
[sp]Don’t[/sp]

You do not have to that on this type of problem.

Go to File>Exit and it should fix it self.