Its funny you should say that, because that happens to me all the time. I asked someone else what they thought it was, and they said it was probably because I had touched the arrow keys. No, I haven't. Funnily enough, it has also happened whilst typing out this reply, and it is well annoying. I can't wait to find out why this happens! Although it doesn't save what I have typed, I find that I am typing in a straight line, then all of a sudden, I am typing in a line about three paragraphs back. Why? someone must know?