Computer is blacked out at the top of my screen.?

Where my favorites button at the top of my screen "was" is now dark-black. I've tried going to tools & reseting the default setting but no luck. I used the restore & it works for a time but changes back to black after I use the pc. The blacked out portion is under the search bar at the very top. I have no idea how or what caused this. Any help in restoring will be written down for future reference. Thanks!