The process is explained above

There's many online retailers

There is most likely a broken piece of plastic in the trigger assembly. I would just buy another one if I were you.

How old is the gun? Is it used a lot? If you're good at disassembling stuff and putting it back together then you may be able to fix it. If not then I would suggest buying a few one as thier not expensive. There are a few reasons why the darts may not be foreign far. The spring may be worn down. If that's the case the spring can be replaced. The barrel or piston may be congested. Look inside to make sure nothing is blocking the piston. The darts may be to blame. Check your darts, if they are ripped this would cause them not to go far or if they are the wrong darts they won't fire correctly. Make sure the darts are the same kind as the darts that came with the gun and that they don't have rips.

You must buy a digitizer and LCD screen assembly. You cannot remove the digitizer separately so you must buy the whole assembly even if the LCD screen it self isn't broken. The cost around $60. Once you have the replacement, TURN THE PHONE OFF. remove the backing that just snaps on/off (in my case the snap backing was red). Then with a small screw driver carefully remove the screws holding on the black plastic backing underneath the red snap backing. Once the screws are removed and put where they will not get lost, take the black backing off ( once the screws are removed it will snap on/off). CAREFULLY REMOVE ALL CIRCUITRY. Try not to directly touch the circuits as static electricity could short them. the next part is alittle messy and grizzly. They mount the screen/digitizer with very sticky adhesive and the only way I could get the old assembly off was by chipping some of the glass on the corner and prying a screw driver underneath until the digitizer and LCD came off. BE VERY CAREFUL. route the ribbon...