I is there an app wherein I can switch on my laptop camera from my andorid phone, and view the camera output on my phone. I am running windows 7 on my laptop.
Use a chat program like Skype and set it to auto answer when a particular account is the caller.
One suggestion is to install a VNC Server on the PC you wish to interact with.
You will then need to install a VNC Client on the device you wish to use as the remote control. There are a few VNC clients listed on Google Play Store Apps.
With that you can activate other apps such as the camera. While the camera is showing on the screen the view will stream to your remote device. This method would also give the ability to further interact with remote environment as well.
My research has found this technique can work the other way around as well.
+1 for @Chris Navas idea for Skype as an option