Please read the information which is in If a scanner is connected .
If the scanner doen't work after installing Nero , then please check if the PacketWriting Software InCD which may have been installed with it is causing these problems:
The current inCD version has the effect that scanners connected to a parallel port no longer work. The developers are aware of this problem and are currently working on a new version.
Please right-click on the InCD Icon in the tray bar under options the field Enable PacketWriting message when changing.