Quotes from Glen E. Clarke

For instance, if a computer does not power up, you can start testing at the electrical socket; move to the power supply, power supply connectors, power switch, motherboard; and then move to the devices. This process moves through the sequential chain along the possible path that power would flow. Following a possible resolution path from one end to the other is sometimes referred to as the layered or linear approach.

Powerful processor, multiple cores if games benefit from them (however, not all games make use of multiple cores). High-end video system, including specialized GPU to support fast-paced screen presentation. High-end, high-definition sound card. High-end cooling to support the heat generated from system components when gaming is taking place.