Hi, I am Dave, I will help you with this.
1
If the F6 key is not working, try pressing Fn + F6.
2
Some MSI laptops nave an app installed that may be blocking the webcam, click your Start Button, then just type SCM, do you see the SCM app in the resulting list?
If you do, open that and check if the webcam is turned on in that app.
3
If what was not the problem, go to the support page for your laptop on the MSI website to download and re-install the version of webcam drivers they provide.