Help Required! Alarm goes off upon opening the door

I recently bought this 929 94 couple of days ago, and i am having this problem now that when i try to open the door with my key (car doesnt have key less entry) the car alarm goes off.
i have tried opening the door with a duplicate key hoping that the new duplicate key might help as the original one is little bent. but that didnt work.

what can i do to have it fixed, can i fix it my self? if not then where do i need to take it?

ii'll appreciate if anybody can call with solution at 507-382-0723

You need to find the alarm disarm wire in the door to make sure it is working. My guess is that your car originally had keyless entry and the previous owner never used the key to unlock the doors so the contacts inside it are shot.