The YOUR COMPUTER HAS BEEN BLOCKED Tech Support Scam is an web browser advertisement shown by scammy remote tech support companies that try to scare visitors into thinking that they are infected so they call the listed phone number. I want to make it clear that if you see this alert in a web browser then your computer is fine! This is just an advertisement and you should not call the number or purchase any services from them.
Article Link: https://www.bleepingcomputer.com/virus-removal/remove-the-your-computer-has-been-blocked-tech-support-scam