Are you still using an older version of Windows Operating System but like to use Windows 7 theme Wallpapers on your desktop. Or, you are using Windows 7 but don't want to install the theme pack, only want to use the wallpaper of that theme pack. Here; at Free Software Advisor, you'll know hoe to get the Windows 7 theme wallpapers without installing the theme pack. Using 7-Zip ( a freeware) you can extract the wallpapers out of the Windows 7 theme packs.
 

This is a small video tutorial explaining how you can extract the wallpapers from a windows 7 theme pack without installing it on to your machine.

All that you need to do is install the 7-zip " an open source software". Right click on the downloaded theme pack of windows 7 and move to 7-zip > Extract to.  The wallpapers will be extracted to the same place as you can see in the tutorial above.

7-Zip works in Windows 7 / Vista / XP / 2008 / 2003 / 2000 / NT / ME / 98.

Link to Download

Download 7 Zip (to extract wallpapers from windows 7 themes without installing theme)