My 95 ford escort 1.9l wont start after I left the headlights on, I already

[bazan333myspaceit]

went and baught a new battery but? I traded in the old battery and they gave me a new one at the store I purchased the battery, then I installed it, but It wont even crank or make any noise when I turn the key, the lights do turn on though when I turn the lights on. What could this be?