Display corruption / computer freeze a after launch

Hi ,  

i've been playing with SoASE for a while but have ran into a wall since updating to windows Seven.  

The game just freezes a couple of seconds after the launch ( after the intro movie ) . The display becomes corrupted with color squares all arround which are very strange. (i'll try to get a photo if it is usefull). 

The Computer freezes a couple of seconds after the display is wrong and then the sound also becomes strange (the music played correctly until this point).  

I have the latest Windows seven drivers available for 64bit for the Video card ( Ati 4870 )  ,  the motherboard ( asus P5B). I'm using the motherboard sound.  I've tried to run on windowed, recucing the resolution ( its at 1280/860 ) , disable sampling to 0.  Nothing seems to help.  

Any ideas ? i really want to play again Sins. 

thanks.