Check if you have properly inserted the monitor cable to your CPU. To make sure you did, detach the cable first by loosening up the two screws that hold the cable in place to the CPU, then re-insert the cable and tighten the screws.
If that doesn't work, you may open your CPU if your computer is no longer under warranty, remove the video card (the one where you attach the monitor cable) by the edge gradually off its slot, then put it back in. Test for signal. Make sure you remove static charges from your body by placing your hands on the sides of your CPU first before opening the CPU cover.
If this doesn't work, your video card probably is damaged.
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Check if you have properly inserted the monitor cable to your CPU. To make sure you did, detach the cable first by loosening up the two screws that hold the cable in place to the CPU, then re-insert the cable and tighten the screws.
If that doesn't work, you may open your CPU if your computer is no longer under warranty, remove the video card (the one where you attach the monitor cable) by the edge gradually off its slot, then put it back in. Test for signal. Make sure you remove static charges from your body by placing your hands on the sides of your CPU first before opening the CPU cover.
If this doesn't work, your video card probably is damaged.