false alarm?

Clicked on what I thought was a LinkedIn link; got a pop up stating my computer has been attacked and frozen and I need to call Microsoft at phone no. whatever. However, I was able to close the relevant tab(s) and everything seems normal. I ran Smart Scan and nothing was found. Anything to be concerned about here?

The pop-up said MICROSOFT SECURITY WARNING.

HTML: FakeAlert

Pictures >> https://www.google.no/search?q=fake+microsoft+alert&client=ms-opera-mobile&channel=new&espv=1&prmd=isnv&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiDxe_4zN7cAhUELVAKHTbPA0AQ_AUIESgB&biw=800&bih=1280

Videos >> https://m.youtube.com/results?search_query=Html+fake+microsoft+alert

Thanks. The message stated that my computer was locked up, but in fact I didn’t even have to close the browser. I just closed the web page that triggered the pop up, and it has not reappeared. Hopefully, Avast would be able to detect anything that had really infected my computer.