To Turn On or Off Windows Defender using a REG file
1. Download the ON.OFF Reg.RAR here (in DROPBOX, Virus SW, Windows Defender)
2. Save the .reg file to your desktop.
3. Double click/tap on the downloaded .reg file to merge it.
4. If prompted, click/tap on Run, Yes (UAC), Yes, and OK to approve the merge.
5. If you like, you can now delete the downloaded .reg file.
6. If you are turning on Windows Defender, then open Windows Defender, and click/tap on Start now if needed. (screenshot below)
The .reg files below will add and modify the DWORD value in the registry key below.
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender
DisableAntiSpyware DWORD
(delete) = On
1 = Off