This video will show you how to stop another user from editing the registry in Windows 10
1. Press the windows + R key to bring up the Run menu and type regedit and hit ok.
2. Navigate through the following folders HKEY_LOCAL_MACHINE/Software/Policies/Microsoft/Windows
3. You need to right click on the windows folder and add a new key called Windows Search.
4. Now right click on the new key and a DWORD 32bit value and name this AllowCortana, double click on this to check that the value entered in is 0.
5. Restart your machine and it will now say in the bottom bar search windows if it has worked.
6. To revert this either change the dword value in AllowCortana to 1 or delete the Windows Search key we created.
I am not responsible for anything that happens on your machine and these tutorials are to be used at your own risk. If in doubt contact an IT professional.