Great tool for checking DNS settings: https://toolbox.googleapps.com/apps/dig/#MX/
Found this here: https://kinsta.com/knowledgebase/free-smtp-server/
Abridged Version Below:
Stop Windows 10 Forced Upgrade and Get Rid Of All Notifications
The Windows 10 update is terrible, and a huge security forfeit by computer users everywhere. I suggest you dont upgrade and get rid of notifications with this:
If you already ruined your computer and dont want to reformat then this video will show you how to redice the amount of spying windows 10 is doing.