9. Reconnect the DC power cables to the system board and drives.10. Secure the hard drive cable, CD or DVD drive data cable, and the front panel ribbon cable to the securing clip on the side of the power supply.11. Replace the computer cover (see Replacing the Computer Cover).12. Ensure that the correct power supply voltage (115 V or 230 V) is selected, using the red voltage selection switch at the back of the chassis.13. Connect your computer and devices to an electrical outlet, and turn them on.14. Verify that the computer works correctly by running the Dell Diagnostics (see Dell Diagnostics).SpeakersInstalling a Speaker1. Follow the procedures in Before You Begin.2. Remove the cover of your computer (see Removing the Computer Cover).3. Insert the speaker into the chassis of the computer.4. Connect the cables to the system board.5. Replace the computer cover.6. Turn on power to the computer.Removing a SpeakerNOTICE: Route the DC power cables under the chassis tabs. The cables must be properly routed to prevent the cables from being damaged.NOTE: Double-check all cable connections to make sure they are secure.NOTICE: To connect a network cable, first plug the cable into the network device and then plug it into the computer.CAUTION: Before you begin any of the procedures in this section, follow the safety instructions located in the Product Information Guide.NOTICE: To prevent static damage to components inside your computer, discharge static electricity from your body before you touch any of yourcomputer's electronic components. You can do so by touching an unpainted metal surface on the computer chassis.