I usually don't have it that long but someone said that you can add turpentine to thin it down and then it is as good as when you first get it
Disconnect the alarm from its power source, then try starting the car.
Build a giant Faraday cage around your house.
If the alarm is after market then the best idea would be to disconnect it from the vehicles electrical system before it fries something. After that take it back to wherever you had the Alarm installed and have them fix the problem or remove it altogether. If the Alarm System is factory than you should be able to get a hold of a dealership in your area with your Vin number, they should be able to get a code that will unlock the alarm system.
