My son left his car here over the winter ,when we tried to stsrt it the battery was dead. trying to boost it the security alarm starts going off.I tried removing the battery and charging it ,but when I hooked it up again the security alarm starts going off as soon as I reconect the battery

 

Unhook the battery, put the key into the ignition and turn it to the on (II) position. Now connect the battery. Alarm should not go off and it should let you start the car after you disarm the alarm.