Help! My Car Wont Start?

Ok, last sunday i had a new alternator put into my car after battery light came on. Today when I went to work, I accidentally left my headlights on. When I came out to my car I opened the door and heard a strange clicking sound (it sounded like a baby bird chirping) underneath the steering wheel. I tried starting my car but I got nothing, no dash lights, my doors wont even lock and my truck wouldnt even pop with the button. We tried jumping it and still nothing. What is wrong?

Suggestion:

You simply killed the battery! Try jumping it with a better set of cables or putting a charger on it. It is nothing more than a battery issue.