For those who are looking for a very simple, barebones music notation program Crescendo from NCH Software might just be what you need. It doesn't have a lot of bells and whistles but it does what it says it should, and it works great on interactive whiteboards or Windows based tablets. To top it all of it is also free!
Crescendo is a free music notation program for the PC. At first glance it reminds me a lot of PyWare's Music Writer Touch program simply because of the layout and style of the tool palette. When you start to use it though you see that although it does not have the feature sets of the commercial programs Crescendo does make the idea of dragging and dropping notes to create music very easy and intuitive. At first I thought the program was limited to only using treble clef and 4/4 but then realized that you can change these things by hovering over them instead of looking for their controls in a menu.
Crescendo allows for multiple parts and multiple lines in a single system, but all note arrangement and staff alignment is done manually. When you place a note in a measure it stays there and does not automatically adjust when other notes are placed around it. The same goes for bar lines, they must be manually moved left and right as needed. They have no effect on music playback, the system simply plays the notes in the order in which they are placed on the staff. If you place a half note in a bar by itself in 4/4 time the system simply skips the missing two beats and continues on to the next note.
These details aside Crescendo actually would be a very good product to use in a classroom setting, especially with an interactive whiteboard or similar device. Allowing students to drag and drop notes, rests, and move bar lines around in this way would be an excellent way to teach basic music notation concepts.
Crescendo is a free music notation program from NCH Software and is available for download through their web site.