Hi again,
I followed the steps exactly as you told me.
There was no cmdguard.sys left on c:. Fine.
I was able to delete all left program files on my harddrive in safe mode. Very Fine.
There also wasnt a cmdagent.exe running after restart. Perfect.
Then I started the cleanup tool. Same thing as before, got the message that there was no Installation detected. No restart proposed. Restarted anyway.
The registry key I mentioned above is still there.
Still not able to delete it.
Windows Defender still not running properly.
I will attach the last log of the cleanup tool and the log that was created along the "successful" uninstallation: If you need other specific logs please give me a hint.

Thank yo very much, Klaus