Game problems

[mikamo2]

this happens in almost all of my recent games, but is worst in hl2.....

here ic a pic from halo, its pretty bad:
http://img.photobucket.com/albums/v414/Mikamo2/messedup.jpg

everytime i try and find a solution on ati, they tell me to download the latest catalyst drivers, which has done nothing at all to help.

i have:
windows xp sp2
p4 2.8 ghz
ati radeon 9800 pro with all the latest catalyst drivers

 

[Kirkburn]

Do you uninstall the original drivers first? Have you changed cards recently? Do any error messages ever appear?