Re: Adverts, etc.
Not using a Microsoft account when using Win10 is the key step in disabling Cortana. Many of Win10's features e.g. Onedrive, Cortana, Microsoft app store require a Microsoft account to function.
Of course, there are various other tweaks and patches which have been generously contributed by the techies to get rid of the telemetry stuff in Win10. These should be used in addition to not using a Microsoft account.
The only negative drawback is not using Skype... which may be annoying for people who do video calls often. But there are alternatives out there which are better than Skype. Also, you might be able to use Skype without linking it to a Microsoft account.