How to delete branch "DisplayLink" in registry?

[Sammy]

I cannot delete the branch "DisplayLink" in the registry.
Error pops up: "Access denied".
Also for all sub items in the branch. Have difficulties to
install the software because of an access denied error
message and tried now to deinstall the software completely
to be prepared for a new installation.
Have also set the service DisplayLinkManager to manual
and rebooted the machine so that this service is not running.
No success.
I would like to deinstall the DisplayLink software.
Please can anybody help. That would be great.

Regards from Germany
Sam