Is anyone getting this message on their computer? As far as I am concerned I am using windows 10 with no problems.
So, why should go to activate again. My friend says it is a scam...

Not necessarily a scam..

Go to
Settings.
Updates & Security
Activation tab.

That will tell you whether Microsoft believes your copy of Windows 10 is activated.
You can add your product key there if it is not..

Microsoft just issued a Windows 10 features update (version 1607) it is possibly that update requires re-activation...

Thank you very much BobHelm...Cheers