the easiest thing you can do is either go to your local mobile electronics store and tell them what kind of alarm you have and need a new remote probably about 40 dollas. let them program for you and you're set.
OR you can remove it yourself if the problem is not the remote.
first of all you have to be specific what kind of alarm you have and what model. But in general if you don't want the alarm be active theres several things you can do:
1. Look under your steering wheel where this is a cover that covers all your wires (ignition harness).2. Unscrew all the screws holding the panel on.3. Look for taped (if done professionally, T-Taps) and locate where the alarm brain is, usually a black box with alot of wires, mostly likely ziptied, or hidden somewhere under the ignition harness.
Once the brain/box is found you can do several things depending on what you wanna do.
1.remove all of the alarm components. a.unplug the wire harness linking to the brain/box. ( you can leave all the wires in the ignition if you're lazy and wait until you can buy another working alarm, or you can trace all the wires where they came from and remove one by one keep in mind what wires are your ignition wires and which one are the alarm's.) b.for the starter kill wire, you can go here
http://www.directechs.com password "122t" and search for your make/model/yr of your vehicle, look under starter wire, and it will show you the wire color for your car, cut the wires that they have split and rejoined them. (best way is to strip about 1 inch from each end and twisting them together, then grab your self some electrical tape and tape it nice and tight, this also goes for all your other connections that you have removed. tape them nice or you will short them out!)
and that's it, for your siren you can leave it there for future uses.
2.disable the alarm for the time being, and the starter kill. a.remove the fuse from the alarm brain, (look for the wires coming FROM the alarm brain and trace the wire that has a fuse to the wire, probably 2, one being the constant, the other being the parking lights. you can remove both. b.starter kill refer to choice 1, ref b
I hope this helps you out.