The QuickCam software access the webcam's driver settings.
This is the same settings that yawcam uses and they are also accessible from yawcam.
Click: "Settings -> Device (Logitech QuickCam Ultra) -> Device properties..."
This will bring up the native driver's settings page.
From there you can change the zoom level and more.
Apparently I didn't do my tests with the latest drivers
I did tests with an old quickcam for notebooks running driver version 8.4.1 (latest driver is 8.4.8 )
And some tests with a Webcam pro 9000 runnnig driver version 13.10.1216 (latest driver is 13.31.1044 )
Did an update on the drivers for the 9000 cam, but still no problems rebooting the computer. (This was on a Windows 7 computer though, but that's the computer I had access to right now...)
Can you reboot the computer without problem if you are running the software that Logitech supplies with the driver?