Hi, thanks for your quick reply... problably this is a more complicated problem:
there are several models of the quickcam fusion of logitech... most of these models does work with the logitech driver. But I have one of the few models which doesn't work under win7. But in win7 one can install this cam with the update tool, so there is no nee for the logitech driver. A few day ago I used tuneup to clean up my registry and so on and I think from this time, my cam didn't work anymore. It's not listed in the device manager (just a unknown usb device). So I wanted to reinstall the windows update, but I am not able to uninstall it.
As you can see, its listed in the update history, but not in the list where I can uninstall updates. And in my device manager there is no cam, just an unknown device.