144 Adding and Replacing Partslower-right corner of the Start menu as shown below, and then clickShut Down.The computer turns off after the operating system shutdown process iscomplete.2 Ensure that the computer and all attached devices are turned off. If yourcomputer and attached devices did not automatically turn off when youshut down your operating system, press and hold the power button forabout 4 seconds to turn them off.Before Working Inside Your ComputerUse the following safety guidelines to help protect your computer frompotential damage and to help to ensure your own personal safety.CAUTION: Before you begin any of the procedures in this section, follow thesafety instructions in the Product Information Guide.NOTICE: Handle components and cards with care. Do not touch the componentsor contacts on a card. Hold a card by its edges or by its metal mounting bracket.Hold a component such as a processor by its edges, not by its pins.NOTICE: Only a certified service technician should perform repairs on yourcomputer. Damage due to servicing that is not authorized by Dell is not covered byyour warranty.NOTICE: When you disconnect a cable, pull on its connector or on its pull-tab, noton the cable itself. Some cables have connectors with locking tabs; if you aredisconnecting this type of cable, press in on the locking tabs before you disconnectthe cable. As you pull connectors apart, keep them evenly aligned to avoid bendingany connector pins. Also, before you connect a cable, ensure that both connectorsare correctly oriented and aligned.NOTICE: To avoid damaging the computer, perform the following steps before youbegin working inside the computer.1 Ensure that the work surface is flat and clean to prevent the computercover from being scratched.2 Turn off your computer (see "Turning Off Your Computer" on page 143).NOTICE: To disconnect a network cable, first unplug the cable from your computerand then unplug the cable from the network device.
