loud beeping noise and warning

Somebody is trying to scare you into buying something that won't help and likely really will harm your computer if you let them "help". Ignore the warning.

What would Microsoft technicians have anything to do with a Mac? It is phishing.

I am not familiar with Macs having any registry which is a terms I only hear with reference to PCs. It is somebody talking computer gibberish that makes no sense.

I see those a few times a year. Just close the page. The biggest mistake you made was phoning a number which means you might now be on their "potential customer" call list and will get bugged by people with Indian accents calling about how your Windows computer is causing problems on the Internet (another scam for which they will charge you $200 to "fix" after you give them the password to your computer).

Yeah, the obnoxious, loud beep puts you into a panic mode where they hope for an impulsive response. When you read their document you see they have no real information about what is happening computer (they get some basic information such as OS version and browser provided by your web browser to all web sites) and most of what they say makes no sense. They just try to scare the people who know nothing about computers into paying for services which might really put their computers at risk.