Sorry, I meant to ask if the Express is working, aside from the LED not working.
IF its power supply has failed, it is possible you may see a brief flash from the optical port or even the status light. Of course, if the Express is otherwise working the LED itself may have failed, but most likely the entire thing is NG.
I would try a "hard reset", perhaps multiple hard resets, before conclusively determining it's really dead. It is unlikely Apple could do anything different.
Read the procedure and make sure you're doing it right: http://support.apple.com/kb/HT3728