According to my recently-installed (today) Windows 7, my graphics card (GeForce GTS 250) could support Aero with drivers that support Aero. According to NVidia, I have the latest drivers (I upgraded today); I also have DirectX 10 (upgraded ten minutes ago).
At this point, I'm lost; I've nothing to upgrade, yet transparency is not working.
So, what do you need to know to help me get Aero working?