If the touch screen on your cell phone stops working, then chances are your digitizer is broken. A digitizer is simply a thin layer of plastic laid under the touch screen. You'll know if your digitizer is broken because you won't be able to set the alarm, browse the Internet, set your ringtones or use any of the features on your phone. However, instead of returning the phone, you can also quickly fix the digitizer at home.
Fixing a Digitizer
Turn off your phone and remove the battery. Take apart your phone by removing the plastic cover on the back of the phone. Eventually, your phone will be in five or six pieces.
Remove the old digitizer from your phone using a razor blade. The digitizer is usually glued into the phone and onto the touchscreen, so this will take some prying.
Use your razor blade to shave off the plastic bump from your old digitizer. You will be breaking off your old digitizer, but the plastic bump will need to be removed separately. Place the new digitizer into your phone, and connect it to the appropriate daughter board. Your new digitizer should have a plastic bump on it that will fit into the daughter board.
Screw your phone back together, put the battery back in and hit the power button. Your touchscreen should now work.