My key stopped disarming the alarm with no warning only a half hour after the last time I armed it. I have two keys and the batteries are new. I also couldn't pop the trunk with the key anymore. I could get in the car with the metal key, but the alarm went off. Someone suggested that I disconnect the battery to reset the alarm, but this brought on a whole new set of problems.

I took the advice and at first I thought it worked because the alarm was no longer on when I re-attached the negative battery terminal.
Within seconds of firing up the ignition, though, I realized that my seat controls no longer work. Neither do the mirrors , the locks, the windows, the rearview controls, the moonroof, the windshield wiper, the rear defrost, the directionals, and probably some other stuff I haven't figured out yet.

I can't re-sync anything because nothing physically functions, now. I've read the DIY in Benzworld.org, but it assumes that only the automatic functions are not in sync.
When I press the window controls, nothing happens... rearview, nothing, seats, nothing, directionals, nothing, wiper, nothing, and so forth.
I have no clue what to do.
Any suggestions?