A: To remove the light switch and wiring, first turn off the power. Then use a volt-meter to verify that the power is off. Remove the cover plate and switch from the box.
Now it depends on how many wires there are in the box. If there are only 2 wires, then you can disconnect the wiring in the light box and remove the old wiring.
If there are 4 or more wires in the box, you need to determine where the other wires go. One set of wires will go up to the light. The others are going to be power. If there is only one power wire, you either need to trace the wire back to a light, switch, receptacle or junction box and disconnect it and remove the old wiring; or place a new junction box in the ceiling, attic or crawl space, put the power wires in it, put wire nuts on the wires and put a blank cover on the new box. Something to keep in mind when placing the new junction box is it needs to be accessible; not buried behind sheetrock.
You may also have 2 sets of power wires. This is power in and power out. If this is the case, you either need to determine where the power out goes to and run a new power wire to that location; or place a junction box and splice the power wires in it. Place the junction box as I explained above.