The Automatic Way
If you are having difficulties with your Logitech Quickcam webcam, then you may need to update or reinstall the drivers. Hopefully, you can do this in the fairly pain free way. If you are lucky, then Windows will be able to find and adjust for your equipment all on its own.
When you connect the webcam, if you have not connected it before, there should be a little pop-up that mentions the wizard for adding hardware. Click it to pull up the installation wizard and then just follow the instructions. If your particular webcam came with a CD for the drivers, then this is the time to put it in. Otherwise, just follow the instructions and wait for it to finish.
If you need to reinstall or update the drivers, you can also work with the automatic processes.
Pull up your Start Menu, and then right click on the tab My Computer. Click on Properties. On this new screen detailing your system, look on the left for a button labeled Device Manager. Click this to pull up another new window with a list of devices. Your Logitech webcam should be located on the tab for "Imaging Devices." Click it and then right-click on the webcam. First, scan for update. If none are found or this does not solve the problem, right-click and choose to uninstall the drivers. Once this is done, right-click anywhere in the manager and have it scan for hardware changes. It should detect and attempt to reinstall the Quickcam drivers.