weird max 64 bit display problem

[chow choppe]

hi all

 

i am using max 9 64 bit edition .

i have a 256 mb PCi express nvidia 6600 GT card

i had no problems with display in viewports till i was using max 8 before this.

when i installed MAx9 i have starting to see through objects in viewports. in the attached image i can see through the top pink roof which is supposed to be on the top of everything but i can see the glass through it. I am not expriencing this problem if i am in a camera view or a perspective view.what is the problem?

can anyone help?

thanks