Power management of personal computers (PCs) and monitors has the potential to save significant amounts of electricity as well as deliver other economic and environmental benefits. The Environmental Protection Agency's ENERGY STAR® program has transformed the PC market so that equipment capable of power management is now widely available. However, previous studies have found that many Energy Star compliant computer systems are not accomplishing energy savings. The principal reasons for this are systems not being enabled for power management or a circumstance that prevents power management from operating. This guide is intended to provide information to computer support workers to increase the portion of systems that successfully power manage. The guide introduces power management concepts and the variety of benefits that power management can bring. It then explains how the parts of a computer system work together to enter and leave power management states. Several common computer system types are addressed, as well as the complications that networks bring to power management. Detailed instructions for checking and configuring several system types are provided, along with "trouble shooting" advice. The guide concludes with a discussion of how to purchase Energy Star compliant systems and future directions for power management of PCs and related equipment.