When I first got my '02 Astra SXi, unlocking either with the remote or with the key would disarm the alarm. Just recently it's changed its mind - if I unlock it with the remote, the alarm is disarmed, but if I unlock it with the key, the alarm stays set (and scares the s**t out of anyone close by when I open the door). Anyone know how to get it back into the original mode? TIA, Mike