Avensis alarm comes on unexpectedly

[Chuckleman]

Hi, I got an old Avensis (2010) and probs with the alarm.I changed the small battery in the fob but the alarm went off again yesterday. So as its an old car I just want to disable the alarm and so i noticed a comment elsewhere online that the alarm would not be set if I just locked the car using the key in the door rather than using the fob but then I read somewhere else online that this would not work, anyone know which is correct please?