If you are using windows 7 then you can use this Windows 8 theme. Convert windows 7 to windows 8 by installing this windows 8 theme pack. Some people are using Windows 7 still now. Before upgrading use this them and make experience.
Windows 8 Theme for Windows 7
The speed and performance of Windows 8 is better than windows 7 or windows 8 – I think you also know it. The sidebar and start screen of windows 8 are very useful for me.