I just had this problem quite a while ago while, like many others I assume, had blindly installed a windows 7 theme on Windows 8 and it happened to be the New ROG windows themes featured on the home page. (link:
http://rog.asus.com/267682013/news/new-rog-windows-themes/)
How to fix your desktop without the hassle of recovery mode/ Shift + f8 bs & assuming the theme was installed:
1) login to your MS account
2) run Task manager (ctrl+alt+del)
3) click on the File tab and click on Run New Task
4) type in msconfig and run it
5) when the System Configuration window pops up, click on the tools tab
6) find and select system properties, click it and launch
7)once you get to the system window, click on control panel on the directory
😎 click on programs > uninstall program
9) Find the theme file and uninstall it
10) Voila, back to normal. Make sure you get rid of that nasty file ASAP and delete it off your downloads list/desktop to the recycling and make it burn in hell by emptying your recylcing bin with your deleted pr0n.
p.s. this could make a great windows 8 prank too. April is coming up.. :cool: