Invisible walls :S

[Kurtensen]

So I just installed this game on my computer after upgrading my graphics card. I was using an nvidia 8800gt and besides the speed up glitch, it ran pretty well.
Now i upgraded to an Ati hd5770 and the walls are almost invisible, like if i had x ray powers or something.
Does anyone know how to fix this?

Thanks in advance!

[relaxinparadise]

ive got the same video card with the same problem.