I got the same message. Had seen it before. I had clicked on a link in a legitimate website, not on an advertising link. Anyway, fortunately, it was not harmful. I used Crt-Alt-Del to get the Task Manager to pup up and then I closed my browser. Because this was a unexpected termination of Google Chrome, it asked my upon restarting whether I wanted to re-open my browser windows which I did, without see the annoying message again. Best wishes to everyone. Be careful. Many useful or interesting websites have been hijacked with viruses.
Same thing for me. My computer shut down and this phone number appear. I called them and give them by credit card 125$ to sell a software and restart my computer. They told me they was Microsoft service. After this, the bank cancell my credit card. One month later, I received a call from this number asking to me my credit card number because they wanted to refund my 125$ because their software was not good.... I told them that my phone was taped by police; so they close the phone immediatly