Crash on startup

[sp]I’ve had GMod for 2+ years now, and never had this problem. Lately, when I try to start up Garry’s Mod, the loading bar gets done on the main menu but then I get the dreaded "hl2.exe has stopped working. I’ve tried reinstalling with no addons, and when I tried running as administrator it said something about gameinfo.txt was missing.

I am using Windows 7 64bit.[/sp]

Edit:

I had to update Garry’s Mod, derp.