156 Troubleshooting Your SystemTroubleshooting the Video Subsystem1 Check the system and power connections to the monitor.2 Check the video interface cabling from the system to the monitor.3 Try using a monitor that is known to be working.4 Run the appropriate online diagnostic test. See "Using Dell™ PowerEdge™Diagnostics."If the tests run successfully, the problem is not related to video hardware.If the tests fail, see "Getting Help."Troubleshooting a USB Device1 Use the following steps to troubleshoot a USB keyboard and/or mouse. Forother USB devices, go to step 2.a Disconnect the keyboard and mouse cables from the system brieflyand reconnect them.b Connect the keyboard/mouse to the USB port(s) on the opposite sideof the system.If the problem is resolved, restart the system, enter the System Setupprogram, and check if the nonfunctioning USB ports are enabled.c Replace the keyboard/mouse with another working keyboard/mouse.If the problem is resolved, replace the faulty keyboard/mouse.If the problem is not resolved, proceed to the next step to begintroubleshooting the other USB devices attached to the system.2 Power down all attached USB devices and disconnect them from thesystem.3 Restart the system and, if your keyboard is functioning, enter the systemsetup program. Verify that all USB ports are enabled. See "IntegratedDevices Screen."If your keyboard is not functioning, you can also use remote access.4 Reconnect and power on each USB device one at a time.5 If a device causes the same problem, power down the device, replace theUSB cable, and power up the device.