Texture Problem after a random time

Alright, this problem Ive had on all 3 of my computers, I start GMod, go an any level and play around for a while, I did notice a little pink and black thing up in the top right corner but didnt think there was a big problem. Im firing away at the several combine I spawned and the HUD textures all go pink and black, also anything shiney does the same, water too. Any Idea what could cause this?

I have CSS, HL2, EP1, EP2, HL2 Deathmatch, HL2 Lost Coast, Half Life Deathmatch: Source, Portal and TF2, so I know Im not missing any textures. The only addons Im using is the Stargate by Avon, Mckays Stargate Addons, and the Stargate Overloader.

I have already used the search to try and find a solution but Im not going through 100+ posts of idiots who cant understand they need CSS to use the stuff from it. Any help would be great and Im good at understanding instructions so you wouldnt need to dull it down.

From what Ive seen of these forums so far I probably shouldnt expect more than a few sarcastic little shits posting that I should buy a game to make it work since its not just models or textures missing from props etc. But these forums are the best chance Il have at getting help soon.

That is very, very wierd. I suggest you to try to update your video drivers.

On 3 different computers having the same problem (no matter what addons I have installed) Im pretty sure its not the video drivers of my 2 week old laptop with windows 7 on it lol. Plus thats the first thing I tried and there arent any new drivers for it yet.

Edit: and I have had this problem on XP and Vista too so its not because of Windows 7 lol

Hmmm, strangely, I got something similar.
Do you also have that all the characters in the game are pink-black, like the menu text?
If that is the case, I think it is the combination of mods you have, because I’ve got the same problem…