That's a problem with windows. You can press Control+Alt+Delete to open the task manager. From there look under processes, sort by name , scroll down to the bottom under windows processes, find Windows Explorer, right click and restart it. That should fix it. Had that happen a few times to me. It's usually just a software glitch or malware. If that doesn't work you can hard reset the device to it's factory settings. But that should fix it.
Best of luck!