can not install itunes

I have Vista Home Basic and tried to install itunes. I have installed many other programs as recently as last month. When I try to install itunes I get a message "the system admin has set policies to prevent this installation".
We typically run in a user account. When installing software in the past it prompted me for the admin password. This time it gave the error above. I have run in the admin account and get the same error.
I am running Norton 360. I can not find a means to change any policies.
The real odd thing is I can install other software????
Ideas?

Thanks
Bill

Cant you just right click on the installer and select 'Run as Administrator...' ? Remember itunes installer also installs drivers for iPod.

See this thread for a possible resolution. MAKE MY IPOD COMPATABLE WITH WINDOWS VISTA !!!

Tried that one and 'can't install itunes, any suggestions?'
The right click method works, thanks Mark.
I tried thinking it would not since I have tried to install it as the admin and that failed. Thanks again.