You need to boot in fail safe mode (press and hold F8 during boot to get there) to be able to do that. Finding that out was how I spent my afternoon hours today.
And that still didn’t help the Nero Cover Designer installation problem (neither does the solution presented in the FAQ).
However! It seems that my seek & destroy operation in the registry (sought and killed all mentionings of Ahead and Cover Designer) finally did the trick. Just as I was trying to reproduce the problem for publishing more data about it here…
Well, all is well that ends well.