Before going over how to fix hardware, we first need to explain what all the different things in a computer do. We are going to focus on desktops for two reasons. The first is that most of the components are much larger and it's easier to see how everything fits together. The second is that laptops tend to be much more difficult to troubleshoot effectively. Keep in mind that even though some of the hardware may look different in a laptop, all computers contain hardware that does the same basic things.

Mother Board

This is the main circuit board of a computer. The motherboard contains the connectors for attaching additional boards. Typically, the motherboard contains the CPU, BIOS, memory, mass storage interfaces, serial and parallel ports, expansion slots, and all the controllers required to control standard peripheral devices, such as the display screen, keyboard, and disk drive; sometimes you will find that the motherboard has other integrated devices such as an audio card and video card. The motherboard is the largest circuit board in most computers and is held on by several screws.

Central Processing Unit (CPU)

The CPU is the brains of the computer. Sometimes referred to simply as the processor or central processor, the CPU is where most calculations take place. In terms of computing power, the CPU is the most important element of a computer system. Apple previously had a partnership with IBM to manufacture their processors. The IBM processors were known as PowerPC processors. Apple has since switched to Intel processors, which will allow for higher processing speeds

Random Access Memory (RAM)

A type of computer memory that can be accessed randomly; that is, any byte of memory can be accessed without touching the preceding bytes. RAM is the most common type of memory found in computers and other devices, such as printers. There are various types of RAM, including Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDR-SDRAM), and RDRAM (Rambus DRAM).

Power Supply

Every computer has a power supply to change the electricity from the wall outlet into electricity the computer can use. The capacity of a power supply is measured in watts. A typical computer requires 400 watts to operate. This isn't very much, when you consider that an average hair dryer uses three and a half times as much power.

Parameter Random Access Memory (PRAM)

Parameter Random Access Memory (PRAM) is a special battery-powered form of random access memory in certain Macintosh computers where vital system information such as the date and time are stored. PRAM also contains computer configuration information, such as what's connected to each port on the computer. Because PRAM is powered by an internal battery, the information isn't lost when you turn the computer off as it is with regular RAM.

PRAM occasionally gets corrupted as the result of an application failure and needs to be zapped or restored. The procedure of "zapping the PRAM" will be discussed in the PRAM and Desktop File portion of this site.

PRAM Battery

The battery which powers the PRAM. PRAM batteries can vary in size, shape, and price from one Apple model to another; below is pictured a PRAM battery that is typically found in a G3 tower. PRAM batteries will last a user between 3 to 6 years depending on how the computer is used.