User Guide
Page 90
... that the problem is with the external keyboard, you are using a mouse extension cable, disconnect it on the keyboard blink during the boot routine. 3. Reinstall the touch pad driver - NOTE: If you are using a keyboard extension cable, disconnect it for the pointing device... option. (The computer automatically recognizes a USB mouse without making any setting adjustments.) Test the mouse controller - NOTE: Use the integrated keyboard when working in the Dell Diagnostics. Disconnect the keyboard cable and check it and connect the keyboard...
... that the problem is with the external keyboard, you are using a mouse extension cable, disconnect it on the keyboard blink during the boot routine. 3. Reinstall the touch pad driver - NOTE: If you are using a keyboard extension cable, disconnect it for the pointing device... option. (The computer automatically recognizes a USB mouse without making any setting adjustments.) Test the mouse controller - NOTE: Use the integrated keyboard when working in the Dell Diagnostics. Disconnect the keyboard cable and check it and connect the keyboard...