I purchased the DCC starter set with two engines and DCC controller.  I tested and ran both engines on my DC layout with no problems whatsoever.  Then I removed the DC power and connected the DCC power and removed my isolated districts for DC.  when I put the first engine on, I selected the default "3" and it worked perfectly.  I then placed the second engine on after removing the first only to have nothing happen.  It would not respond in any way.  I went through all of the programming steps and nothing, I even tried to run it in analog mode on pre-set 10, but still nothing. 

Santa is getting nervous, any help would be appreciated. 

I notice you wrote you have already successfully tested both locomotives using DC.

Take the non responding locomotive to a model trains store or someone with a DCC system and ask them to reset the decoder for you by programming CV 8 with a value of 8. And test run it on their DCC system.

No access to someone with a DCC system then,
Carefully follow the procedure on page three of the E-Z Command Setup and Programming Instructions under REPROGRAMMING DECODERS WITH PREVIOUSLY ASSIGNED DIGITAL ADDRESSES.

Still no success getting the locomotive to work, then contact the place from which you purchased to exchange the whole set.

Cannot exchange the set for another set, contact Bachmann Service Dept by phone for your options.