Not long ago I discovered Portable_Ubuntu_for_Windows.
Because of this thread, I have ended up experimenting with Linux music score editing programmes whilst running Windows XP.
The Portable Ubuntu installs easily and puts a small toolbar at the top of your screen and that acts as he Linux programme start bar, then the Linux programme windows open on top of the Microsoft windows. Because the Linux goes through an intermediate level things are not quite as fast as running as the actual system, but it allows you to try things out, and Music notation doesn't need to be as fast as shooting zombies...
Downloading and installing programmes under the LINUX is pretty straightforward and I have been playing with MuseScore and NoteEdit. I have downloaded Rosegarden which is some form of sequencer with score capability, but haven't had time to mess around yet.
The two I have tried will output PDF scores and other things such as MusicXML files (portable to a lot of other programmes) and MIDI files.
I preferred the note entry with Muse Score, but NoteEdit put lyrics under melody line easily.
It is worth trying out.
The Portable Linux is a strange thing. Applications which will open as a text file (e.g. ABC or Music XML) can be copied from the Linux and then pasted directly into a Windoze application, but actual files such as MIDI cannot be copied from one to the other without some geek type setting up to network the "Linux computer" and the "Windows computer" systems.
Quack!
GtD.