Now comes the desoldering. If you have never done this before, you may want to read this: How To Solder and Desolder Connections

In all, there should be 7 wires that need to be desoldered: 2 that are connected to the speaker, 2 that are connected to the screen, 2 that are directly connected to the battery and 1 that is connected to a thick wire that feeds into a sticker on the battery.