By default any user can launch registry editor. This could cause issues if users start to amend or delete keys or values, so should be secured.
1) Browse to %SystemRoot%\Windows\system32
2) Right click on regedt32.exe
3) Click properties
4) Click on the security tab
5) Remove all groups except administrators and system
6) Click apply and ok
7) Repeat the above steps for file Regedit.exe if it exists in the same location