Annoying rendering glitch

[immibis]

Ok, so I just bought the Orange Box on Steam, and downloaded and started playing Half-Life 2.
But I have an annoying glitch, where sections of floor disappear when I stand on them. In narrow corridors the walls also disappear.
Screenshot:

OS: Windows Vista
Graphics: Mobile Intel 945 Express Chipset Family (crappy laptop graphics)

Has anyone else had this problem or know how to fix it?

Edit: If I turn on an option such as mat_normalmaps (which shows normal maps instead of textures where applicable) I can see the normal maps for the ground, even in the areas that don't get rendered normally.
Edit 2: The problem only seems to happen for bump-mapped materials. Disabling bump-mapping does not fix the problem, however.

 

[Vegeta897]

Your screenshot no worky.

Edit: Yeah I went to the link, it just doesn't work for me.

 

[immibis]

Click here to see it then (although it works fine for me)

 

[Hectic Glenn]

Hmmmm, usually the first step we recommend most people to do is validate their files with Steam (to ensure there are no errors in the game files) but I don't think this will solve your problem.

I'd recommend searching for the most up to date drivers for your graphics chip firstly. Secondly, have you tried fiddling with the settings to optimise them for your relatively weak laptop? Dropping texture quality may help.

Also I'm not sure what level directx that card operates at but you could try forcing the game to run on directx 8 by right clicking the game in your games list, properties, then 'launch options' and add this -dxlevel 80 (no space at the start, just between the l and 8).

Good luck.

 

[immibis]

Thank you. That appears to have fixed the problem (although I might just be in an area where it doesn't happen). It also increased my FPS significantly in large areas.