Reconnect your PC and check your HDMI cable
First, check that your PC is turned on and make sure that it is not in Sleep mode. Completely disconnect the HDMI cable from your TV and PC, then reconnect it. Use of a certified cable is highly recommended. Using a non-certified HDMI cable may cause connection issues, or your screen may not appear properly.
How to use the HDMI Troubleshooting function
You can use HDMI Troubleshooting to check the connection between your HDMI cable and the external device.
- Press the Home button > Menu > Settings >Support > Device Care > Self Diagnosis > HDMI Troubleshooting
Note:Click the link for more information onMy TV doesn’t detect a device connected via HDMI.