I don't get the MS nag when I use Win 7 because I did not install or uninstalled the "nag" updates. These are them if one wants to avoid the nag. Be sure to make a backup of your registry before editing it in case you make a mistake. You can look these up on-line, but the MS description of them is often vague and misleading since they want everyone to stop using Win 7, alas:
KB4493132 - notify end of support for Win 7 date
KB3173040 - reminder of June/July 2016 deadline July 29 for free upgrade to Win 10
KB3150513 - “upgrade enabling” patch
KB3123862 - lets users easily learn about Windows 10 or start an upgrade to Windows 10
There are also a couple of Register entries one can change if uninstalling those "updates" doesn't do the trick - if those keyword don't exist one can create them and set them as described:
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Gwx
Under this key, the 32-bit DWORD value “DisableGwx” is set to 1 or completely deleted.
These will be referred to as the “Gwx” key and the “DisableGwx” value. This key and value control the display of the “Get Windows 10” offer icon in the system tray. When DisableGwx is set to 1, the upgrade offer icon is suppressed.
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate
Under this key, the 32-bit DWORD value “DisableOSUpgrade” is set to 1 or completely deleted.
These will be referred to as the “WindowsUpdate” key and the “DisableOSUpgrade” value. This key and value control the downloading and installation of any upgrades to Windows. When DisableOSUpgrade is set to 1, any previously downloaded Windows 10 files are deleted and Windows will never attempt to upgrade the current operating system.
