can't disable car alarm

I have a 91 BMW 3-series with an alarm, keyless entry, etc. I do not think that the alarm is stock but can't say for sure. I do not know the brand of the alarm. A few days ago the battery in my remote entry keychain died. I needed to get in the car anyways so I used my key to unlock the door. The normal alarm (multi-sound cycle) went off when I closed the door but then when I locked the door with the key the alarm disengaged. I then unlocked the car and was able to start it with no problems. The next day I needed to put something into the car. I unlocked it just fine, the alarm was still disengaged, but the thing I was putting into the car banged against the under-carriage of the car by the driver-side door causing some non-normal alarm (a repeating single tone) to go off. This incident also disabled the ignition and locking/unlocking the car using the key did not disengage it. I got a new battery for my remote entry but no combination of buttons (it has several) has any effect. I also disconnected the car battery to no effect. There are two buttons on the dash (one looks like it has a sun-beam-like pattern on it, the other is plain) that seem to be related to the alarm (in the past pushing the buttons would cause the alarm to chirp). I have tried various combinations of button pushes while putting the key into the ignition to no effect. Can anybody give me some idea of how to reset my alarm?Nate

Sounds like a clifford valet button, you would have to know the combination to override.

The single tone sound like your factory alarm, that alarm should reset by using your key on the door try both just in case. As far as your aftermarket i would get under the dash and find out waht kind it is. Then google instructions for it

i've tried the key in all doors and in the ignition, no luck.Nate

It has been a very long time since I had any dealings with a Clifford alarm.  But most alarms require the key to be in the ON position before the valet button will work.