You can end the explorer.exe process then start it back up again, typically clears up that kind of stuff.
 
Mittens suggestion works wonder, you can also create a .bat that does the same thing if this will become a recurring problem for you:

@echo off
taskkill /f /im explorer.exe
start explorer.exe
 
You can end the explorer.exe process then start it back up again, typically clears up that kind of stuff.
To fix without restarting you can CTRL+ALT+DEL then go to Processes>Right click on "explorere.exe" and end process.

Now go to File>New Task(Run...) and type "explorer.exe" (no quotes). Click OK.
Nah restarting explorer.exe didnt do anything