Sometimes you can not run Regedit. This is due to a setting in the registry itself.
When you try to run Regedit, you get a message like “Registry editing has been disabled by your administrator” or something similar.
To resolve this run the following command:
REG add HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System /v DisableRegistryTools /t REG_DWORD /d 0 /f
This should get you the instant result.