|As riider mentions, replacing a power supply is a relatively simple thing to do. It may look like a lot of wires, but they break down to a few types. A large 20 or 24pin connector for the motherboard (its socket is obvious if you or someone already unplugged everything), A 4 Pin CPU/motherboard connector (some performance systems use an 8 pin one) that plugs in typically near the CPU, a bunch of 4 Pin Molex connectors that may or may not be needed for accessories (IDE hard drives, IDE optical drives, and others), a few SATA power connectors (SATA drives), and possibly 6Pin (or 8PIN) PCIe connectors for gaming video cards. Some of these may not be on your stock power supply but all will be on a good one like riider listed above as a recommended replacement. There will always be spare connectors for adding and expanding your system.|
If you have any specific questions on any one connector, just ask.
If you were actually talking about internally in your power supply, stay away!! If you do not know, it is dangerous, if you do know, you would also know that it is not worth the bother.
You have to be a little bit crazy to keep you from going insane.