After uninstalling Sophos SSL VPN Client, windows gives the error message at start up:

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Sophos SSL VPN Client
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Error opening registry for reading (HKLM\SOFTWARE\OpenVPN).
OpenVPN is probably not installed
I have checked windows Registry:
HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
And the StartUp folders:
shell:common startup
%PROGRAMDATA%\Microsoft\Windows\Start Menu\Programs\StartUp
shell:startup
%AppData%\Microsoft\Windows\Start Menu\Programs\Startup
Task Manager startup section also checked.
There is a similar questions here, with an insufficient answer.
Where can I find the settings that starts up Sophos SSL VPN Client, so that it can be removed and windows starts without displaying this error message?
