Plz can someone help??

Just came home from work 2 find my classic terzo making a constant buzzing noise from the alarm.Tried the key fob but nothin is happening and the car is locked.dont really want to open with the key and set the alarm off.
the car has been parked up for a couple of weeks but unsure if this is the prob.

all help appeciated thanx

 

your car battery is flat...

open the car then either jump start it or remove the battery and charge it