sool

I was just uploading some tracks from my Mz-Nh1 to the pc, when SonicStage2.1 stopped working. Now my Nh1 is still working in PC-MD mode, but I cant turn it off. I had this problem some month ago. I solved the problem by puting out the battery, but so all my music was gone. Can anyone help me what i can do to not lose my music again, or how to turn off my Nh1?