Microsoft have paid imminent focus to personalization in Windows 7, and present it with a magnificent collection of desktop backgrounds and themes. Users of Windows 7 can also create their own personalized themes and then share it with other Windows 7 users.
But there is a good news for the user of older version of Windows(like: Windows XP or Vista), that they can also enjoy these Windows 7 themes applying some simple tricks.
For this initially you have to launch the official Windows 7 themes directory and download some of the themes you like for your Windows XP or Vista desktop.
All these files have a unique .themepack extension which is just another zip format containing all of the elements of a theme including the background images, Aero glass colors, sounds, cursors, icons, screen savers, etc.
To consume these files on Windows Xp or Vista, you first need to extract the zip file, since only Windows 7 can natively understand the themepack format. You can either change the file extension of the Windows 7 theme file from .themepack to .cab and then extract the files with a right-click.
Once extracted, your theme files will now be in a new folder that has the same name as your original themepack.
Now you have all the required files, after this you will have to activate the Windows 7 theme on your non-Windows 7 computer.
If you are working on computer which is running Windows Vista that supports Aero, simply double-click the .theme file that is present in the them folder you just extracted. This will set your windows border glass to the color of the Windows 7 theme and your wallpaper to the default background of the theme.
Windows XP does not support Aero glass, but you can still use the background images from downloaded Windows 7 theme on your XP desktop. You can find the backgrounds inside the themepack folder itself or in a sub-folder named DesktopBackground. Pick any image, right click on it, and select “Set as Desktop Background.”