Gmod crash on startup

Hello everyone,
A friend’s Gmod crashes when he launches it, and his Steam freezes so he has to exit Steam too. He has tried reinstalling it a few times, and it didn’t work. Since I couldn’t help him, I asked him to send me his crashdumps so you guys maybe could fix it. I am no technician when it comes to those sorts of things, so here are the crash dumps: http://www.mediafire.com/?638fiv9d9py8qxd
Thanks in advance

If this happens only to gmod , goto (Gmod>settings>Local files>Verify integrity of game cache , if that does not work Delete your second garrysmod folder
(Garry’s mod>Garry’s mod)

If it happens to every other game , redownload steam.

He says he already did all those things. Any other suggestions?

bump

Steam shouldn’t crash because of gmod, if he completely reinstalled steam then he has to be having some issues with his computer that is most likely out of the reach of this subsection. Have him do a fresh install of gmod, removing all workshop addons, legacy addons, etc. Reinstalling steam and trying again.

Desktop or laptop? Windows or mac? Graphics card?

Post these specs, they might have the solution. Also is this only for gmod? Or all of his other steam games?