Motherboard

The main circuit board inside your personal computer is called as motherboard. You may be wondering about the purpose of this circuit board. The purpose is to provide a platform for all the other components and peripherals to talk to each other. At some point, every component communicates through the motherboard, either by directly plugging into it or by communicating through one of the motherboards ports. The type of motherboard depends on the central processing unit design. It can be categorised by which socket type they have, for example: Socket A, Socket 478 and so on. The type of motherboard is very important, as it will need to house your CPU, and they are not interchangeable. A motherboard will show you what type of socket it has.

figure 2.21
Figure 2.21 Socket 370 processor socket
Source: http://en.wikipedia.org/wiki/CPU_socket

figure 2.22
Figure 2.22 Inside a typical system unit
Source: http://www.mtsac.edu/~rpatters/CISB11/Chapters/Chapter_03/Figures/Fig03-06.jpg