Image remains on screen when closed

When I open 2 or more images at the same time, the last image to open is the only that is visible.  I click on one of the others or the other, but the image doesn't open - the last image stays on the screen no matter what I do.  I've been using Adobe for 15 years+ and have never had a problem like this.  Even when I close the image - it still remains on the screen while the title disappears from the bar.  Help!