when I load ntworthy composer on my m/c using win2k I can see all the notes in my score but the staff lines disappear after the first screen. ie the first screen looks ok but when you pan along the score they are no longer there.
Your system has a buggy display driver. See https://forum.noteworthycomposer.com/?topic=2166 and https://forum.noteworthycomposer.com/?topic=2465 for details.
You can also use the F9 key to have NWC refresh your screen. This enables you to work around the display driver bug.