You may need to restart Windows Explorer for registry changes to take effect or to restore explorer after its crash, generally what all do is either log off or restart PC and there are other tricks as well to restart Explorer not so recommended and most used method is killing Explorer.exe process in task Manager and running again from Run Command, there is more simpler way to restart Windows Explorer in Windows 8, here it is.
Restarting Windows Explorer in Windows 8
1. Press Ctrl + shift +Esc to open the Task Manager
2. Select Windows Explorer process and Restart button appears at the bottom click it. Even right-click on Explorer.exe in Task Manager offers more options including Restart and End Task.