In the menu "start" in the installed programs look for files whose name contains the model of your webcam or camera English words and abbreviated cam. If you find such programs succeeded, most likely, they will help you to enable the built-in webcam. Try to run them. Depending on the configuration and design of the laptop near the camera to illuminate the led, indicating that it is enabled and working. When you turn off the webcam led turns off at the same time.
If your laptop was not pre-installed software, you install the whole system from scratch, use third party software to enable the built-in webcam. Download and install, for example, a small free utility Broadcaster StudioPRO. In addition to enable the built-in webcam, this program will help you to capture and save to file any streaming video that is playing on the screen or gets into the camera lens, and start my own video broadcast.