Definition Update for Windows Defender--cannot prevent, no MSE

I cannot prevent Windows 7 "Definition Update for Windows Defender" critical updates from automatically installing, no matter the settings ("never check for updates", or "check for updates but let me choose whether to download and install them"). I've never had MSE installed on this computer (since 2014) to my knowledge, and MSE does not show as being installed on this desktop PC, so cannot uninstall MSE. These Definition Updates for Windows Defender show in "View Update History," however they do NOT show in the "Installed Updates" list, so cannot uninstall them. (1) I need help to prevent the continued forced Definition Update for Windows Defender updates; and, (2) how do I uninstall the Definition Update for Windows Defender which have already been installed? Thank you!

Windows Defender and MSE are two different programs.
Windows Defender is built into Windows 7, it is an Anti-Malware program, not an Anti-Virus program.
Here's a tutorial that shows how to turn off Windows Defender:
Windows Defender - Turn On or Off

The definition updates can't be uninstalled.

Thank you. I have set the control to "Do not use this program".

So, just to double check, is there no way to uninstall the KB915597 Update?

There is no way i know to uninstall the WD definitions updates.
Maybe turning off WD removed the Definitions stored in Windows, i don't know.

thank you again

You're welcome.
Thanks for marking the thread solved and Welcome to Seven Forums.
:)