...and this might sound dumb, but have you tried signing out and closing the hotmail page, then turn your computer all the way off, start it up again, sign back into hotmail, and see if that works?

I think I need to do something else.

Most Hotmail settings - I don't have an account.

However - the long line of writing going on forever. This sounds to me like a window has become resized to an enormous width and the right edge of the mail windown in which you are typing, is hidden off screen.

You need to resize this window so that you can see all four edges on your screen. I'd imaging that when you type a new message, Hotmail automatically wraps the text (on to the next line) when it reaches the edge of the window.

So try clicking and dragging on the top bar of the mail window, see if you can move it around. I can't be more precise than this, not being able to look at your screen and Hotmail. If you can move it, haul it over to one side then position your mouse on the visible edge until you see a double headed arrow and drag it inwards to reduce the window size.

That's all I got. Good luck.