how it works
What they do
power supplies convert an alternating current (power from your house) to a direct current.
You can usually see the at the corner of your computer, as the cooling fan and the power cord receptacle are on them.
why they have so many wires
each of the plug thingies attach to the hard drive and other things, to give them power. Some laptops need more power than others but they cannot have as many programs.