Does the gun click when you pull the trigger or does the trigger move without seeming to actually operate the mechanism?
If it clicks but the gun doesn't fire then it's a problem with the firing pin, the firing pin safety or fouling in the firing pin channel.
You can test the firing pin safety and verify that the channel is clean by removing the slide, holding down on the firing pin safety and shaking the slide back and forth. You should hear the firing pin clinking back and forth in the channel.
Now release the firing pin safety and shake the slide again. You should hear nothing.
If it passes that test, detail strip the slide (there are videos on youtube) and check to see that the firing pin is intact.
If it's not even clicking (like a dryfire) when you pull the trigger then it's a problem with the trigger spring, connector or trigger bar. You can check to see if the trigger spring is broken. If it's not a broken trigger spring, it's probably time to get an armorer involved because something's wrong with the gun--there's no way that the trigger bar and connector should have worn out that fast.