76 Adding and Replacing PartsBefore Working Inside Your ComputerUse the following safety guidelines to help protect your computer from potential damage and to help ensureyour own personal safety.CAUTION: Before you begin any of the procedures in this section, follow the safety instructions in theProduct Information Guide.CAUTION: Handle components and cards with care. Do not touch the components or contacts on a card. Hold acard by its edges or by its metal mounting bracket. Hold a component such as a processor by its edges, not byits pins.NOTICE: Only a certified service technician should perform repairs on your computer. Damage due to servicingthat is not authorized by Dell is not covered by your warranty.NOTICE: When you disconnect a cable, pull on its connector or on its strain-relief loop, not on the cable itself.Some cables have a connector with locking tabs; if you are disconnecting this type of cable, press in on the lockingtabs before you disconnect the cable. As you pull connectors apart, keep them evenly aligned to avoid bending anyconnector pins. Also, before you connect a cable, ensure that both connectors are correctly oriented and aligned.NOTICE: To avoid damaging the computer, perform the following steps before you begin working insidethe computer.1 Ensure that the work surface is flat and clean to prevent the computer cover from being scratched.2 Turn off your computer. See "Turning Off Your Computer" on page 75.NOTICE: To disconnect a network cable, first unplug the cable from your computer and then unplug it from thenetwork wall jack.3 Disconnect any telephone or network cables from the computer.NOTICE: To avoid damaging the system board, you must remove the main battery before you service the computer.