it could be that you had your trigger stop is set to far out so that after thousands of trigger pulls with nothing to stop the trigger but the microswitch that the screws holding the microswitch in place broke or the switch itself broke.
could use more info, like have you opened up your grips and looked where the microswitch is while pulling the trigger? does it wiggle around, or does it just not shoot?
if it wiggles around when you pull the trigger then you probably just need a new screw to refasten it, and if it just doesnt shoot, then i'd check two things:
1. if you have taken your frame off recently, check that the noid wires aren't broken. (if you haven't taken the frame off, then I highly recommend that you continue not to unless you really need to)
2. check to make sure you have a fresh battery in the gun, actually.. this should probably be number 1