For anyone not being able to activate "aero" even wehn they have a GPU from NVIDIA may find this useful,
http://public.www.planetmirror.com/pub/guru3d/nvidia/?l=330&fl=
or search: 9746-vista-x86-[Guru3D.com] on google.
After days of trying to get the Aero theme this has been the only driver to work for me, Its great and raised performance score to 3.4
iMod