Licecap is a free amazing desktop screen recording software. with this you can capture active window screen. This will give you a animated GIF image record of your active window.
You can record a Gif image of your desktop by using this Licecap.
To download this go to this link.
let me tell about how to use Licecap.
Click on Licecap.exe and click on record. give a name to your file and start record. click on stop when you finish.