battery drain

When i got my 94 jetta i activated the door lock alarm and heard a humming noise coming from the trunk. since then my battery wont hold a charge. what might be the problem.

all the things you've listed as maybe problems are normal. have you thought that maybe the battery was dead when you bought it? have you bought a new battery yet?

The battery was replaced before I bought it. It worked fine for about a week and then I turned on the alarm. Everything went downhill after that. What is that humming noise?????

someone in here mentioned that noise. I'm pretty sure they said it was the locking mechanism.

It's a vacuum pump, the door locks operate on vacuum. Unless it runs for a very long time it wouldn't drain the battery. Have the battery tested and the electrical system checked for current draws. I would avoid taking it to a chain that sells batteries as they have a tendency to replace when it's not really necessary, I'd take it to a full service repair shop.