Mike may have been hacked, but there isn't a lot of apparent damage from it. He uses Windows 10, and he got a blue screen with a number to call regarding spyware. He called the number and they wanted remote access to the computer. Norton said the app was safe, but he didn't like what was happening and so he turned it off. Leo says that's wise. Microsoft will never contact users regarding spyware or anything else. So Mike was wise to realize it was a scam before they got any money out of him. But they may have installed even more malware on his computer with the remote access app. Chances are, there was a browser popup that triggered a fraudulent blue screen, but is actually a webpage. Here's how it works - https://www.zdnet.com/article/microsoft-beware-this-fake-windows-bsod-from-tech-support-scammers-malware/
And here's a link on how to reset a PC safely.
Chances are, they didn't install anything too bad. But if he wants to remove all doubt, the only way is to back up the data, format the hard drive, and reinstall Windows from a known, good source. Then update it. But since Mike realized it was a scam almost immediately, they probably didn't have time to install more malware on it.
Mike was wise to trust his "spidey sense" on that, to be sure.