Enable Regedit.

Sometime after your pc infect certain virus then you clean it use antivirus software one of the effect, the virus script usually vbscript, disable some funtion in Window OS. The popular
funtion that the virus disable Regedit. Here i show how to enable it back use Gpedit.msc.

1. Run > gpedit.msc (Press enter). Group policy editor will appear.
2. User configuration > Administrative Templates > System
3. Double click on "Prevent access to registry editing tools".
4. Disable this option (Yes, disable. If you enable this option Regedit will be disabled)