Ok I have an MSI GT70, did you try activating it via the toolbar at the top of the screen that comes on MSI laptops. It looks like a tiny paperclip at the top of the screen in the center, there should be once you open that toolbar up an option to activate the webcam.
Desktop, mine has 7, there should be something top center on the desktop. The webcam is handled by windows drivers, when you activate it, it will auto install.
Heres a picture of my laptop, I circled what im talking about.
http://gyazo.com/2ddf55b749e812ad4656108931c72175
If you highlight it, you bring up this menu here
http://gyazo.com/4047af5b7e28789db985a401330cbe92
Now try clicking this symbol, it turns the webcam off and on, when turning it on, it will auto install.
http://gyazo.com/b9f56f48fd98db4259e3724c0d5554b6
Excuse the poor quality of images, I did this quickly in paint.
Hey, pal! I have the same exact laptop, MSI GS70, has been going alright for a year until it had some monitor issue, so I sent it abroad for maintenance.
Only problem is when it came back it says the camera's not connected. I uninstalled the drivers due to an advice that it'd automatically reinstall, but no luck.
So, have you found any solution for this? Or what did you do? I've been desperately looking for solutions.