Hi DirkW,
Just since few minutes ago after uninstall and reinstall both LV7.0 German and PCI-CAN\2 v2.2, the system works again properly, I did not undertand why. Thanks for that tool, I used it to be sure that reg is free of any NI products hidden files, nothing has been found. Also I asked NI-Support in Munich and they mentioned that from LV 7 on this tool is not necessary any more (... Normalerweise sollte dies ab LV 7 nicht mehr nötig sein).