Onboard computer Problem

Hello,

I just got a good deal on a 92 BMW 325 with only 125000 KM. There are some problems leaking oil and some cooland that I asked the mechanic to fix.

That is not my problem though. there are some electrical problems that my mechanic does not now how to fix it.

Even when I close all the doors and even if I take the key out of the ignition the beeping wouldn't stop. Also the batery seems to be drained.

If I listen closely to the onboatd AC/Heating pannel there a little motor noise that wouldn't come off even with the key out of the ignition. This seems to drain the battery.

The jerk that had the car before had a stereo system and he actualy ripped off the whires from the player and in the trunk there the amplifyer is.

I am not intereswted yet in making the stereo work but to get read of the anoying noice.

Also the computer on the right pannel does have the lights behind the buttons lit, but the screen does not show anything. I checked the whires and they seem to be connected in the back.

What do you suggest. I am new to this car but I am eager to learn more.

Thank You.