Malwarebytes saved the day today! Yesterday I had to make a service call to my daughter's store computer to remove Windows 10 (and put it back to Windows 8) which was suddenly installed, because settings were to automatic download and install and than I also run a full scan of Microsoft Defender, it found one Pup and removed it but today when restarting it, a blue screen scared them at the store, so I had to make another visit. The scary display showed to call Microsoft and not try to restart the system because there was the option that it wouldn't load but it also mentioned that this problem is caused by a virus! I managed to download a new version of Malwarebytes which found a lot of more Pups (a quick scan with Defender before didn't show any) and after cleaning them all and I dared to restart it, it loaded without problems!
I always loved to use Malwarebytes and did it today even more! It saved many other computers for me in the past from deleting all data from a hard drive which some professionals recommended!