Q: how to connect my built-in camera to my macbook?

I have not been using my built-in camera for one or two months already and if i were to use, I would normally use for skype. However, now when i wanted to use the photobooth, they showed me that the camera is not connected. I tried to reboot, used the sudo killall VDCAssistant in the terminal also force quite the VDCAssistant in Activity Monitor. All of which did not work for me.

Now, I cannot even use my camera for skype. Is there a way for my macbook to detect back my camera?

I just bought my macbook pro retina display 13" and has been using less than 6 months.