"Critical Alert from Microsoft" is a scam that happens at least one in every 10 minutes while browsing. It happens on Chrome and Edge. I had Norton Support take over my computer and he removed McCaffey (to save his job, rather than fix).
He also used a third party software to try to remove the problem and then used Norton Power. After 15 mins, he said he cleaned everything. The problem was still there and unaffected.
There is info online about this problem, but the simplest solution is SpyHunter for $39. The foreign Norton Support was not aware of this scam and asked someone, then he went to a third party software.