Unbearable graphics problem

So ever since…idk when actually, it just randomly started happening, and got worse and worse…
My guns are pretty much all black, and most props and all npcs (with the exception of rollermine and turret) are black, distorted and patchy…I CAN’T TAKE THIS ANYMORE!
I have it a little in TF2, but not at all in portal, alien swarm, HL2, or non-steam/valve games.
Anyway, what the hell do I do?
PICS INCLUDED!

So as you can see, my 357 is un-seeable and kleiner isn’t lookin’ too hot.

And there’s my physics gun

If you want anymore pics, just ask

http://www.facepunch.com/threads/1026395-HL2-Bug…?