Assistance, please?

I am not sure if anyone’s gotten this before but:

How do I go about fixing it?
Only my Sniper and Pyro models work, the rest have this black texture either as their faces or the entire model.

Have you tried re-installing TF2/Verifying the game cache?
Did you buy Gmod legally?
What are your specs?

Reinstalling TF2/Verifying Game Cache? Doing that right now.
Did I buy it legally? Yes.
My Specs?

Processor: AMD Anthlon 64 X2 Dual Core Processor 6000+ 3.01 GHZ
Memory: 3GB RAM
Graphics Card: NVIDIA GeForce 9600 GT
Hard drive space: 466GB