• Connect the keyboard to the back of the case – Older model motherboards use a 5-pin connector, but most computers use a 6-pin PS/2 port. Sometimes the keyboard connector and port are color-coded (violet) to distinguish them from the mouse.
• Connect the mouse to the back of the computer – The mouse is the next device to connect, usually right next to the keyboard connection if it is a PS/2 mouse. Follow any color codes (green) where applicable. If it is a serial mouse, plug it in the serial port. Some motherboards number the ports, and since it is the first serial device in the system, plug it in serial port number one.
• Connect the monitor – If the motherboard has video capabilities, the connection point will be near the mouse and keyboard connections. If the motherboard has a video adapter card, plug the monitor into the connector located on that card. Since the connector is quite large, it normally has two screws to help hold it in place. Twist the tops of the screws until the connection is secure.

Plug the AC power cord into the back of the power supply and the other end into the wall socket. If there is a switch on the power supply, turn it on as well. This usually will not power the computer. It is just the master power switch for the power supply. The computer is normally started with the power switch on the front of the case.

The computer can now be turned on.