First off I have a 97 Camaro 3.8 five speed. I have the original keyless entry system that came with the car. I was outside today checking my fluids and I finished so I closed the hood. I don't believe I set the alarm (I don't really remember for sure). So I go inside my house to look for some stuff to work on my other car and I get down into my basement and I hear my alarm go off.
I run outside and try to deactivate it, but it doesn't work. I tried the button on my remote a few times and nothing happened. So I ended up just popping my hood again and taking out the fuse to my horn so it wouldn't keep beeping. I could still hear something electric clicking on and off although my horn wasn't going off. I then decided to continue to look for the stuff to work on my other vehicle and I went out to the Camaro after that and it had stopped making the clicking noise. I put the fuse back in and it has been fine ever since.
Does any body know what could have made my car do this? I really haven't messed with the keyless entry system too much yet so I don't really know what it could be.

 

Put the key in the ignition, and turn it to the "run" position. This deactivates the alarm.

Electronically locking the car (via remote, or interior power lock switch) re-arms the system.