POSSIBLE SOLUTION:note: I own a DELLhmmmmmmmmm ... this seems familuar 
.. I have a 7900GS (256MB) Nvidia video card running on Vista (32bit) platform. After getting beta's 1,2,3 I had same issue ... I won't go into details (PoorMan looks @ Stardock) but I did find a driver to work properly with Sins.
I recomend trying this to fix your issue.
Driver Version: 7.15.0010.9746
I have noticed no change to the look of Sins or other applications w/ this driver!
You may have a hard time finding it (for some reason I could not find it in Nvidia's archives) so here is Nvidia's link:
http://www.nvidia.com/object/winvista_x86_97.46.html
I hope this helps.
TO Stardock/IC: Maybe a look into this would be good for .03 patch?
PoorMan(toldyaso)DSO