How do you build a computer from scratch?

First, you need to select a motherboard that supports the type of CPU that you prefer (Intel or AMD.) The rest of the components that you select need to be compatible with that motherboard. For example, the type of RAM will depend on what the motherboard specifies. Major components include: Case, case fans, power supply, CPU, CPU fan, RAM, hard drive, optical drive (DVD or CD), multi-media drive (for camera cards), video card, modem (?), etc... It is generally pretty easy to put the parts together. Once that is done, hook up a monitor, keyboard, and mouse; power it up; and install Windows using the installation CD provided. Here is a web site that provides more details:http://techreport.com/articles.x/13671. Good luck.