Help gta iv is un playaball

Hello,
iv installed Grand Theft Aoto IV and im haveing a problem.
I can't see walls , bildings , roads , i can only see lamp posts and bins. This makes it vary hard to play. iv been trying and trying to find out the problem but no luck, iv updatted my g card drivers, my windows , and diyrect x , everything, im shore iv dont it all but the games patchs!!! im downloading as im typping, i dont think it will help tho. i use:

micosoft windows xp home
version 2002 sp3
intel R Core (TM)2 CPU
6400 @2.13GHz
2.14GHz, 1.00 GB of RAM

NVIDIA Geforce 7950GT diver version 6.14.11.8084
SoundMAX integrated digital hd audio
TSSTcorp CD/DVDW SH-S183A

can you help :-)