Curious dead battery / car alarm problem.

[camelzi@xxxxxx]

So yesterday I left my car lights on for the whole day. When I got back

to the car, the battery was dead.

I managed to jump the car with cables of a colleague and thought I
would be fine.


However, now it happens that everytime I open the door some kind of car

alarm would start for about 20 seconds.


The thing is, I don't have a car alarm! Well, I was never told I had
one, and I don't have any electronic device to turn it off.


Do you have any idea on what I should do?

BTW, I have a 2004 Chevrolet Aveo I bought from CarMax in December
2005.

Thanks,
Carlo