Windows Vista - Logitech Pro 9000 installation trouble

I have a Logitech pro 9000, which turns out to be an excellent webcam.
I installed the server under my account in Windows Vista with
administrator rights. It works quite well.

However, when I open another account, I am confronted with "Windows is
trying to configure your webcam", then another window "your software
cannot be found". It seems the installation is looking for some *.msi
file to run it. This cannot be stopped. After close or abort the same
windows open again, searching for the software.

I do not want the other account to use the webcam, nor to install
anything there. Can I switch that off. My idea is that the device
driver of Logitech cannot find the configuration for the other user,
so it starts an installation. Can that be stopped without harming the
installation for the main user?

Logitech asks me to reinstall the software, deactivating any Microsoft
driver support during the installation. This is a pain in the ass.

Thanks for any ideas.