Checkerboard Texture error.

My computer is a: Hp Dv6 1030us
OS: Vista Home Premium 64
CPU: Intel Core 2 Duo T6400 2.0GHz
Graphics (Integrated Card): Intel GMA 4500MHD It ran Crisis no problem, so it shouldn’t be a hardware problem. But who knows, I could be crazy.
Ram: 4GB DDR2

There are a boatload of mods I have installed, and I’m just trying to get them all set up in my own chaotic way. I can give you a list, but I’ll wait until somebody asks, because this shouldn’t even be effected by mods, because it’s a problem in my stock maps.

On the stock G-Mod Maps, I’m getting a purple and black checkerboard as a texture instead of the proper texture on somewhere around 30% of all textures in the maps. I’m also having the same problem in multiple mods. Especially props. But unless a stock/mod conflict is actually causing this, lets stick to talking about the core maps please. I can fix the mods later.

I’m also missing the icons for the following maps:
Gm Easy Engine Build
Gm Easy Engine
Gm Ship 2

Is this simply because I don’t have HL Episode 2, and hence, I might be missing some textures?
Or am I making a serious mistake in my problem identification?

I’m actively working on the problem for the next two hours, and will be checking back here often.