If it doesn't recognize the webcam, go to Start > Control Panel > Hardware and Sound and open Device Manager. Expand the Imaging Devices and Universal Serial Bus controllers lists, right-click on the webcam driver and select Uninstall. After that, reboot your computer, plug in the webcam and press Scan for hardware changes icon from Device Manger. If it still doesn't work, I suggest you to use another webcam capture utility from Software Informer database. Many of them are free of charge, easy to use and fully compatible with all major webcam models.