Active window bar, menu bar missing or hidden

Today after opening a PDF, my active window bar (at the top) and the Acrobat menu bar wouldn't display. It's Acrobat 9.5.5. Instead of giving me the normal active window bar and menu bar, it would give a gray Acrobat buttons menu. Each time I get it back to normal via F9, it doesn't stay that way. It's extremely frustrating. I cannot find any preference setting to fix this back to normal for good. Please help. Thanks.