Test the mouse controller —To test the mouse controller (which affects pointer movement) and the operation of the touch pad or mouse buttons, run the Mouse test in the PointingDevices test group in the Dell Diagnostics (see Dell Diagnostics).Reinstall the touch pad driver —See Reinstalling Drivers and Utilities.Video and Display ProblemsFill out the Diagnostics Checklist (see Diagnostics Checklist) as you complete these checks.If the display is blankCheck the battery —If you are using a battery to power your computer, the battery charge may be depleted. Connect the computer to an electrical outlet using the AC adapter,and turn on the computer.Test the electrical outlet —Ensure that the electrical outlet is working by testing it with another device, such as a lamp.Check the AC adapter —Check the AC adapter cable connections. If the AC adapter has a light, ensure that the light is on.Connect the computer directly to an electrical outlet —Bypass power protection devices, power strips, and the extension cable to verify that the computer turns on.Adjust the power properties —Search for the keyword standby in the Windows Help and Support Center (click Start® Help and Support).Switch the video image —If your computer is attached to an external monitor, press to switch the video image to the display.If the display is difficult to readAdjust the brightness —Press and the up- or down-arrow keyMove the external subwoofer away from the computer or monitor —If your external speaker system includes a subwoofer, ensure that the subwoofer is at least 60 cm (2 ft) away from the computer or external monitor.Eliminate possible interference —CAUTION: Before you begin any of the procedures in this section, follow the safety instructions in the Product Information Guide.NOTE: If you are using a program that requires a higher resolution than your computer supports, it is recommended that you attach an external monitorto your computer.