Why Is My Webcam Said To Be Occupied By Another Application And How Can I Get It To Work

I looked thoroughly over the web and found no useful solutions. I reinstalled webcam driver, I uninstalled all instant messaging software, even uninstalled the pre-installed Windows Life bundle provided with the original OS (Windows 7 Home Premium).

The funny thing is that I tried to use the webcam log in feature by Toshiba, which enables to log into Windows after configuring the face image, and camera turned on and I was able to complete the configuration, which means that the hardware is OK, and it’s something wrong with the software on the PC. Does anyone have any clues?