Registry Regedit.exe - Access Denied even when Owner

Error / Issue: You are unable to delete a registry key even though you have full permissions and are also the owner of the key.

Fix: Use PsTools

not a conventional fix but when has that ever stopped you 

1. download PsTools / PsExec

https://docs.microsoft.com/en-us/sysinternals/downloads/psexec

2. Install / Extract PsTools

3. Open Command Prompt as administrator and navigate to pstools folder

e.g

cd C:\Users\username\Downloads\PSTools

and then run

psexec -i -d -s c:\windows\regedit.exe

or

psexec.exe -i -d -s c:\windows\regedit.exe

you now should have full access to make registry changes , hoooray willie nelson