Background to problem and how it all started:
I suddenly and without warning had errors related to plugins. Specifically, firebase services and firebase testing plugins not enabled. Result, could not open my project.
After lengthy research and struggle I was finally able to enable these plugins (along with others)through a miracle and opened my project BUT a new problem has now emerged.
Now the run app button for the emulator is greyed out. If i try to go to the top and click on: RUN APP ==> the "run green" button is also greyed out here (along with "debug" and "Run with coverage".
When I open a recent project in Android Studio in a new window the emulator run button is visible and I can open the Emulator without any problems. It's only suddenly this one project. It's been working just fine until now.
I updated Android Studio just prior to this as it requested it. I am using Android Studio 2.2.1.
Any suggestions highly appreciated, thanks in advance