Motherboard/CPU

Your Processor is attached to your motherboard, every part of your computer is connected to the motherboard. That's why it's called a CPU (Central Processing Unit). Parts like CD/DVD Drives, Floppy drives are connected through an FFC, Flat Flexible Cable. Other Parts like A Video card or a Sound card are attached through slots on your motherboard.
There are different types of slots. PCI-Express is the newest one. Other ones like AGP and PCI should be in your computer right now if your computer is about 1 - 2 years old. The things your attach have to fit into the slot, there are 64 bit and 128 bit slots and whatever you need to attach should be right, or it won't work. There are some motherboards that have some PCI slots and then a few PCI-Express slots.

In class, we saw an internal modem and a Sound Card fixed into a motherboard. An internet model is for people who use Dial-up, it's that annoying sound making thing that you wondered about at one point in your life. Modem is short for Modulator Demodulator.