One of the great things about the days of the doorstop salesperson is that you could slam the door in their face if you weren't in a buying mood. It's not a hint that Microsoft was willing to take, constantly harassing Windows 7 and 8 users to make the upgrade to Windows 10. Thankfully, the firm has made it known that it is possible to disable the notifications once and for all, as long as you're prepared to get your hands dirty. If so, then you can use this tutorial to amend the registry, blocking any access to the upgrade path. At the same time, Microsoft is relaxing the rules as to who can upgrade their system to Windows 10, enabling small businesses and similarly small organizations to get in on the action.