How do you turn off the alarm on a 1997 Jetta and can you deactivate the alarm system?

Read your owner's manual. This information can be found there.

AnswerYou turn off the alarm on a 1997 Jetta by unlocking any of the 2 front doors. The alarm is temporary disabled when opening the trunk. If you set off the alarm because you replace the battery then you have to lock and unlock the doors to turn it off. First, lock all doors, including the trunk. Then reconnect the battery cables. Finally, unlock the doors. Instead of unlocking one of the front doors, you can also disable the alarm. This can be done by, after locking your car - which automatically arms the alarm, wait a few seconds and then turn the key the other direction for about half a second. This disables the alarm, yet leaves the door locked.