trouble with full-page printing

Hello everyone. I am having trouble printing a full page piece of music. I use windows XP, and for the majority of my music (possibly pieces that run over one page) the music is condense to the top-left two thirds of the page, leaving a substantial amount of the page blank. The second page of music actually begins on the first sheet of paper, but 75 percent cut off. Then, on the second sheet of paper, the second page of music begins again, not cut off, but still only occupying two thirds of the page. Does anyone know how to assure that the entire sheet of paper will be filled with one, and only one page of music?

Jordan