If you are having problems with themes in Windows 8, it is entirely possible that you have to restart your Windows 8 themes service.Windows 8, Microsoft's brand new operating system, provides options to choose among many themes available for its appearance, to suite users' tastes and moods. If you are a user of the Windows 8 operating system then there are certain steps you have to follow and these steps are:
Step 1: Open the Search.
Step 2: Now type service.msc into the Metro search bar and press enter. Now click on the Services option.
Step 3: The list of Windows 8 services appears. Now you can scroll down, hit T on the keyboard to jump to Themes.
Step 4: Select THEMES and then Click on Restart link to restart the service
The service will automatically as you click on it. If you have the problem of it not restarting then check your graphic drivers.