Motherboard Stained Glass Window

Laptop computers generally use highly integrated, miniaturized and customized motherboards. This is one of the reasons that laptop computers are difficult to upgrade and expensive to repair. Often the failure of one laptop component requires the replacement of the entire motherboard, which is usually more expensive than a desktop motherboard due to the large number of integrated components.
Bootstrapping using the BIOS
Motherboards contain some non-volatile memory to initialize the system and load an operating system from some external peripheral device. Microcomputers such as the Apple II and IBM PC used ROM chips, mounted in sockets on the motherboard. At power-up, the central processor would load its program counter with the address of the boot ROM and start executing ROM instructions, displaying system information on the screen and running memory checks, which would in turn start loading memory from an external or peripheral device (disk drive). If none is available, then the computer can perform tasks from other memory stores or display an error message, depending on the model and design of the computer and version of the BIOS.