Garry's Mod won't launch (from steam..)

[whatnow V2]

Hi all, I haven't played garry's mod for about 4 months and now I decided to play it... except it wont start. It does not get past steam launching.. just stays at "launching garry's mod.."

I have PHX3, wiremod, etc, but I don't think that matters.

specs
CPU: i7 920 @ 4GHz
RAM: 6GB DDR3-1600MHz CAS8
GPU: Galaxy GTX 470
OS: Windows 7

edit:
I do run the steam UI beta.

I don't have a problem reinstalling garry's mod, but I'd rather try other things first.

any ideas?

thanks,

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UI Beta is kinda buggy on i7 cores.

[whatnow V2]

:saddowns:

thanks anyway