Yesterday I was out and about and the keyless entry worked just fine. When I returned home and turned the car off, the alarm began to go off and never stopped. This is a system that was in the vehicle when purchased. I eventually had to disconnect the battery to make the alarm go off. I have tried everything from changing the batteries in the keys, to checking for any blown fuses. Please if there is anyone with any information that can help me I would greatly appreciate it. Oh, yes the car still starts (after I connect the battery) and all the lights work. 
PLEASE HELP!!!!

have u located the reset toggle that is usually under the dash or in the kick panel? in most cases, if u hold the reset switch and trigger the alarm, it will reset. hope this helps.