car battery is completely dead. can I manually unlock car without setting off the alarm. fob does not work

The Alarm won't go off if the battery is dead. And when you replace it, just have the FOB near you to click the alarm button if it goes off when you install a new battery.

If the battery in the car is dead, the alarm will not go off. Once you unlock it, if it does go off, put the key in the ignition and turn it to the "on" position. It shouldn't go off though if the battery is dead. The alarm might go off when you jump start it though, so be ready to turn the key to get the alarm to stop.