My laptop has a built-in webcam. I was doing video capturing using webcam. Suddenly, the webcam could not function. Then I tried to restart, hopefully fix the problem. After restart, there was a taskbar notification mention that there is an unrecognized malfunction USB device. (I am using Windows 7)
So, how to solve this problem? This was not a driver problem. And I thought that maybe the webcam was broken or some hardware problem.
Since it was a USB device (mentioned by Windows), I tried to use USBDeview. Run USBDeview with administrator privilege. Select all the items in the list. Uninstall them. Restart the computer.
Then, Windows will detect the USB device (built-in webcam), and install the device correctly.