Need help to reset a rooted Fire to factory

I tried rooting my brand new Fire and it worked ok, but decided to reset to the factory software. When I did that, my ability to play video was disabled. Tried resetting twice, same result. Called service, worthless.

Any tips on how to undo a root job and truly restore the factory software to a Kindle Fire?

So as an update, I used the TWRP utility and the following instructions to reset a rooted Fire to factory. Worked perfectly, problem solved!

http://www.jayceooi.com/2011/12/28/h...le-fire-video/

BTW, here's the rooting utility that I installed originally; it had the TWRP utility on it so I just used that per the above video.

http://liliputing.com/2012/03/root-k...e-utility.html