If I open a PDF file or some other kinds of files, I can't figure out how to quickly exit and get back to the desktop. In other Windows versions, the handy Escape key or Back arrow would do that. Now, if I press Escape nothing happens and I have to reboot the computer because the PDF takes up the entire screen whether I like it or not. And pressing the arrow just makes the PDF smaller. There must be a quick answer to this; I am so frustrated I can't think of anything else to try. Thanks in advance for help.