If you are getting objects that have unnatural coloring (bright blue/green usually, though rarely can be invisible/transparent) then from my experience, you may have damaged your RAM. >_<;;
I've had this happen with several games before and it was because I had kinda sorta cooked my RAM and needed to replace it. >_>
Basically, it seems that the graphical textures of the neon colored objects are getting loaded into damaged sections which can't be read from properly, so you end up seeing the underlying background texture of the object. (Usually the same color as bluescreens/greenscreens used for movie compositing.)
I could be entirely wrong and misguided on the technicalities behind what you're seeing, but the solution of replacing the RAM has always worked for me... Except that one time that it was the memory on the graphics card, which was thankfully still under warranty. :x
You might want to look into doing some hardware diagnostics. Odds are good that it's not actually a Windower issue, but a hardware/component problem.