ford fairmont ?

I have a ford fairmont 1980's model car with an imobolisor cyclops in .Today I washed the car and the alarm went off quite ear peircing , so then I killed it with the key under the bonnet.Turned the key and it stopped but when I turn the key again it is still going the alarm. The flashing light in the car does not work and now I can not turn over my car .How do I turn off the alarm please and have my car going again?