The primary function of a computer case is to protect the computer's components from harm. A secondary function is to easily transport the computer from place to place.
Computer components, such as the motherboard, hard drive and power supply, are vulnerable to damage from dust and spills. The case keeps the components in a protected environment for optimum functioning. Cases contain vents to provide airflow and keep the computer at the right temperature. Cases also provide some user interface, including a power button, access to drives and plugs for peripherals. Light signals integrated into the case give information about the computer's functioning.