The command system on my e430 just started displaying no changer when I hit the cd button and will not play my cd's???? Do I need a new changer?

 

yes.

try disconnecting-reconnecting the battery to reset it.

 

so as I understand this, it has been working, then suddenly stopped?
can you think of any other symptoms which manifested themselves
right about that time (even if appears coincidental)?

yes, you can disconnect NEG cable from battery but be aware that
you may need to reset, resync some appliances such as outside
mirrors, seating positions, moonroof....

another intermediate method (before NEG lead disconnect) would
be to pull the radio fuse for a few minutes.

or, slide out the head unit and disconnect the power (block connector)
and after making a cup of coffee, return and reconnect. best to connect
the changer to the head unit (plugging in orange fiber harness) to the
changer while the power is off....so that it 'wakes up' to the changer.

the attempt is to disrupt power and cause the head unit to reset. do
you have onboard cell phone? if not, then the fiber circuit should be
direct from head unit, to changer, and back to head unit.