Disconnecting the battery will not 'reset' the compressor. Assuming that you have the proper key, it will not prevent you from starting the car or trigger the alarm.
Disconnecting the battery
will cause your radio to go into security mode (dead) until you enter the security code - it'll ask for it. If you don't have the code, you should because a battery could always fail, old, accidentally leave the lights on, etc.
If you take the serial number from the radio and send it to me in a PM, I have the software to retrieve your radio code for you.
