Jon, I have had the same problem and had fixed it by first disconnecting the negative terminal (connector) from the car battery, then with my alarm remote ready in my hand, I placed the negative connector back on the negative battery terminal. At that point the alarm sounded and I was quick to disarm. Everything was back to normal except my stereo presets and clock were gone due to the disconnect.
Hope this helps.
However, I am now having the same problem that even a disconnect will not fix:
I was in haste to charge my battery while connected to the car (I have done this before with no problems). Now, I have the same problem, and even the disconnect and reconnect do not fix it. I do not know if the two are related. We will see...
Jeff, December 2006