Hello Stefan, ( I am writing from Amsterdam).

Thank you very much. Your suggestions worked. First I changed the computer system preferences, and I was still not able to search, so I changed the LW prefs, and was also not able to search. Only then did I remember that I should restart LW before the effect would take place. Once I had re-started LW, I was able to search.

Therefore I do not know which of your tips did the trick! But I am muchly appreciative for your help.