Graphical errors on L4D2

[[ [ DUMPY GRIMBO ] ]]

I just got my old computer repaired and restored by a friend. Now, Im having problems with L4D2. The infected appear white with bright yellow clothes, and if I turn a certain direction, the entire screen turns black.
My specs:
Windows Vista home premeum
about 17000000 megs of RAM
AMD Athlon(tm) 64 processor 4000+ 2.60 GHz
32Bit OS

Note: Its an E Machines thats over 4 years old. I don't know if thats affecting anything, but any help will be greatly appreciated.

[HolyNumber]

What's your graphic card?

[MyBooMStick]

sounds like your computer is to old