DIY PC building involves assembling a personal computer from individual components rather than purchasing a pre-built system. This process allows users to customize their machines according to specific needs, such as gaming, graphic design, or general use. Key components include the motherboard, CPU, RAM, graphics card, storage drives, and a power supply. To start, gather all necessary parts and tools, including a screwdriver and anti-static wrist strap. Follow online guides or tutorials to ensure proper installation of each component. Once assembled, install an operating system like Windows or Linux to complete the setup and enjoy your custom-built PC.