Can't get the alarm to shut down

I noticed there was corrosion building up on the positive post and disconnected the battery to clean. After doing that I tried to connect the battery again and the alarm was going off, I can't get it to shut down. I've had this car for 3 years and when I purchased it it didn't come with a control. I'm assuming it's a factory one. It's happened before when I replaced the battery 3 years. Is there anyway to deactivate the alarm so it doesn't happen again? Thanks.