Microsoft is pushing Windows 10 hard. If you don’t upgrade, you get barraged with notifications and some people even report that Windows 10 is being installed without their permission.
If you don’t want Windows 10, there’s a neat Github project that stops the Windows 10 reminders, aptly called “I Don’t Want Windows 10”:
Windows 10 offers some improvements, but it’s not necessary for many folks. If you’re happy enough with Windows 7 or 8 on an old computer, you shouldn’t feel pressured to upgrade. Try “I Don’t Want Windows 10” to stop the pestering messages.