62 Removing and Installing Parts8 diagnostic lights (4) Use the lights to help you troubleshoot a computer problembased on the diagnostic code. For more information, see"Diagnostic Lights" on page 47.9 hard-drive activity light The hard drive activity light is on when the computer readsdata from or writes data to the hard drive. The light might alsobe on when a device such as a CD player is operating.10 power button,power lightPress the power button to turn on the computer. The light inthe center of this button indicates power state. See"Specifications" on page 105 for more information.NOTICE: To avoid losing data, do not use the power buttonto turn off the computer. Instead, perform an operatingsystem shutdown.11 USB 2.0 connectors (2) Use the front USB connectors for devices that you connectoccasionally, such as joysticks or cameras, or for bootable USBdevices (see "System Setup Options" on page 110 for moreinformation on booting to a USB device). It is recommendedthat you use the back USB connectors for devices that typicallyremain connected, such as printers and keyboards.12 vents For adequate cooling, do not block any of the vents.NOTICE: Ensure that there is a minimum of two inches ofspace between all vents and any object near these vents.NOTICE: Keep the vent area clean and dust-free to ensurethat the computer is adequately ventilated. Use only a drycloth to clean the vent area to avoid water damage to thecomputer.
