This manual follows the Haynes traditional format of lavish illustration and concise text in a logical progression from selection through operation and maintenance to provide best value from the subject of the manual. Most computer users buy a packaged system from a computer shop or from a manufacturer. Even large corporations rarely build their own computers but issue a specification and accept a proposal that more or less meets that specification, usually including something beyond the stated requirements. Sometimes a product that does not really meet the spirit of the specification will be delivered. A computer is a complex blend of hardware, firmware and software. Many different combinations will each be capable of meeting general computing requirements. A challenge facing the majority of users is that they either do not know enough to specify what they really need, or they trust a supplier to know what they need. The easy answer is frequently to purchase the apparently cheapest machine that claims to do everything the user thinks is needed. The result is that few users receive a computer that best fulfils their particular requirements and they have to adapt to match the machine. Building a computer to provide exactly what is required is much easier than many users think it will be. Essentially it is a matter of deciding what functionality is required and then looking at the available components to meet the needs. That may then require some compromises because of the constraints of budget. At least, the user gets to decide rather than having to accept someone else’s compromises. To provide lowest cost computing, the user needs only to buy those components that will collectively provide the required performance and capacity with the functionality that is needed. To meet the most demanding requirements, the user can source the highest quality components and create a computer that has the highest performance and ensures service by including duplicated components that can be individually changed when they fail without requiring the computer to be switched off and without losing data. That represents a very wide financial range, where typical package products sit somewhere close to the lower end of the price range and often very close to the bottom end of the range for value. This manual explains what components are necessary for particular tasks, how to choose the most suitable and how to put them together. Most readers will be very pleasantly surprised to find out how easy it is to choose and assemble the components to create exactly what they need in a computer.