Another thing you can do is to highlight your writings after a paragraph or so, go to edit at the top of the page (if you are using Netscape) and just copy your work. Then continue writing and repeat the process every so often. If by any chance you should lose anything, it won't be the whole composition, as you can just paste the last copying back on to the BB and continue. This is what I usually do as I've experienced the same thing as you.

Or you could do it as others have said, just go the Word or Wordperfect or whatever and then just paste it on.