If you have used a desktop computer or have a dual-monitor setup, you have likely seen the "No-input Signal" error message on your computer monitor. The error message may point to a number of culprits. Accordingly, the solutions run from simple to complex. Prior to attempting advanced troubleshooting methods, check the connection first. Power off the computer and the monitor. Remove the cable that connects the monitor with the computer, then reseat it. Try a different port, if possible, then reboot the computer.
Connect the monitor to another computer if possible to eliminate the monitor as the faulty hardware.
Shut down the computer. WARNING: Before you start troubleshooting remember that you are dealing with electricity that can KILL. http://www.kitchentablecomputers.com/static.php - rules
Only work inside the computer case when the power has been switched off and disconnected. Never open the power source. Some of the below steps recommend removing physical parts within the computer. While in the computer it is highly recommend that you be aware of ESD and its potential hazards Remove all cables and devices plugged into the computer. Make a note of the port into which your monitor is plugged. Remove the left side panel when facing the front of the case. Unscrew screws or manipulate latches to remove the side panel. This process varies according to the type of case you have. Please consult your manual if you are unsure of how to remove the side panel. Attach the antistatic wrist bracelet's clip to a metal object, then ******** the bracelet. Locate your video card. (This will be the card that contains the port with which your monitor interfaces.) Remove the slot cover screw that secures the card into the slot. Remove any power cables that connect the video card to the power supply. Pull the card out of the slot. Examine the gold pins to check for any damage. Reseat the card if it physically appears to be undamaged. You should hear a click once the card is secure in the slot. Screw in the slot cover screw. Attach the power cable from the power supply unit, if applicable. Leave the case open for now. Reconnect only the monitor, power cable and any devices required to boot the computer, then restart the computer. Shut down the computer again if you receive the "No-input Signal" error message again. Remove any cables and devices you plugged in to restart the machine. Remove the video card with a spare or replacement by following the instructions above. Connect necessary cables and devices to reboot the computer, then restart it. Shut down the computer and remove cables and devices if the display still won't work. Unplug the power supply's cables from all devices on the motherboard. Make a note of each plug-in so that you can correctly connect all devices with the new power supply. Remove the screws that mount the power supply. Fit the new power supply into the mounting area, and screw in all screws. Attach all required power cables to devices connected to the motherboard. Attach the cables and devices required to start the computer. Reboot. Hope this helps.