Based on some previous posts I decided to remove power completely from the car on the theory that voltage fluctuation caused my car alarm to "lock up" and prevent it from starting. I thought reducing the voltage to zero may 'reset' the alarm system. I had just begun to remove the positive cable from the battery. As soon as I turned the nut, the alarm began blaring. Everything was back to normal. Interesting, there was no visable corrosion on the battery terminal. My theory is that somehow as the battery discharged (for still undetermined reasons)it produced some minor corrosion that prevented current to the alarm system (a separate wire attached to the postive battery terminal). The wire to the rest of the car remain unaffected since everything else seemed to work and voltage was OK as I attempted to jump the car. I still need to figure out why my battery occasionally discharges. Thanks to you who provided suggestions. Bob Thomason #5252