Aero not available, PC is capable

Installed RC1, clean install.

I have a HP Pavillion DV2000T. 2.16 Intel Core, 128MB Nvidia Force 7200, 2
GB RAM etc.

In the Appearance and settings i do not have the option for aerio, only
Vista Basic. I have followed the instructions in the Windows Help file....
and the nvidia drivers are up to date. Any suggestions? ( display settings
are 32bit, refresh rate is 60hz, theme is windows vista....) Appearance
settings is were I can't get the aero option.