Slide disappears when I move the mouse near it.

I am trying to start a new project after about two years. The first thing that happens is that there is a dark void; I have to move the cursor around to find the first slide. But after about 6 seconds, it disppears. I then put an image on it, after which it disappears again. If I don't move the mouse while it is over it, it doesn't disappear. And when it does disappear, it is still visible on the filmstrip. If I add a second slide, the same thing happens.