my friend came the other day and he unlocked my car using the key and the alarm went off, then he used the remote to turn it off. since then my alarm is disabled but i can use my remote to unlock and lock the car but without any sound. the small switch on the bottom is on.

how do i enable my alarm again? pls help

 

Year of the car and make and model of the alarm?

 

its an after market alarm. on an honda accord 99