HDMI No Signal PC

Step-by-step checks before you replace parts

HDMI no signal on PC

When a Windows PC is on but the monitor shows HDMI no signal, treat it as a decision tree. Start with power and the video path, then branch — do not jump straight to opening the case or replacing parts.

What does your monitor say?

Monitor makers word the same problem differently, and the exact text varies by model. Match the message on your screen:

“No Signal” or similar “No Signal” (ASUS, Acer, LG and most others), “No Signal Detected” (BenQ), “Input Signal Not Found” (HP), or “No HDMI signal from your device” / “No DP signal from your device” (Dell). The monitor is on and set to an input, but no picture is arriving. The PC may be asleep, the cable may be in the motherboard port instead of the graphics card, or Windows may be sending the picture to another screen. Work through the ordered steps below. On DisplayPort, also see DisplayPort no signal.
A message about the cable “Check Signal Cable” (LG, Samsung), “Cable Not Connected” (Acer), “No Cable Connected” (BenQ), or “No HDMI Cable” / “No DP Cable” (Dell). The monitor does not detect a working cable on the input it is set to. Reseat the cable at both ends, then set the monitor to the input you actually plugged into: cable and port checks · input source and Win+P.
“Out of Range” or “Input Not Supported” A signal is arriving, but at a resolution or refresh rate the monitor cannot show. This is not a cable fault. Go to monitor out of range.

Pick your situation

Check this first. If the PC never shows BIOS/POST on any cable or port, go to no display in BIOS. If Windows was already running and the screen went dark, try projection mode and a graphics driver reset before opening the case.
Desktop with a discrete GPU Cable in the motherboard I/O HDMI while a GPU is installed → often no signal. Go to GPU vs motherboard HDMI.
Fans and lights on, screen fully black Use PC turns on but no display. If BIOS never appears, see no display in BIOS.
Laptop external HDMI dark Use laptop HDMI no signal (Win+P is often the fix).

Ordered steps

If none of the situations above fits, work through these steps in order.

  1. Confirm the PC has power

    Look for case LEDs, fan spin, keyboard lights, or HDD/SSD activity. Microsoft’s blank-screen guidance also starts with power and a connected display.

    Desktop PC case with power LED highlighted by a red circle
    Confirm power LEDs or fans before chasing the HDMI path.
    No power signs Leave this tree — troubleshoot power/PSU first (not covered here).
    Power signs present Continue to step 2.

  2. Use a known-good cable and the correct output port

    Reseat both ends of the HDMI cable. On a desktop with a graphics card, plug into the GPU ports on the rear bracket — not the motherboard rear I/O HDMI unless you intentionally use integrated graphics with the GPU removed or iGPU enabled.

    Next pages: cable and port · GPU vs motherboard

    PC rear panel diagram with arrow pointing to GPU HDMI port and red X on motherboard HDMI
    Discrete GPU systems usually need the cable in the graphics card HDMI/DP ports.

  3. Set the monitor input, then cycle Win+P

    On the monitor, select the HDMI input that matches the port you used. On the PC, press Windows + P. If you can see the menu, choose Duplicate, Extend, or Second screen only. If you cannot see it, press Windows + P, then press P once by itself, then press Enter. Repeat that sequence for the next mode. PC screen only leaves the external monitor dark, so try the other three modes.

    Next: input source and Win+P

  4. Reset the graphics driver

    Press Windows + Ctrl + Shift + B. Wait a few seconds for a beep or brief flicker. Microsoft documents this reset in external-monitor troubleshooting.

    Next: driver / GPU reset

  5. Isolate adapters, docks, and alternate connectors

    Remove USB-C hubs, docks, and HDMI↔VGA/DVI adapters for the first pass. Test a direct HDMI or DisplayPort cable to the monitor.

    Related: dock / USB-C · DisplayPort · VGA / DVI adapters · out of range

Symptom map

FAQ

Why does HDMI say no signal on a PC?

Common causes: wrong rear port (motherboard vs GPU), loose or failed cable, monitor on the wrong input, Windows left on “PC screen only,” or a hung graphics driver. Start with the decision tree above.

What should I try first?

Confirm power, reseat a known-good HDMI cable in the GPU port, set the monitor input, then Win+P and Win+Ctrl+Shift+B — matching Microsoft’s external-monitor troubleshooting order.

How do I reset an HDMI / graphics path without reinstalling Windows?

Use Win+Ctrl+Shift+B for a driver reset. If needed, enter Safe Mode and update or roll back the display adapter. See the driver reset page.

Monitor says no signal but the PC is on — same guide?

Yes. Use this homepage tree, then branch to power on but no display if you never get an image on any cable.

Official sources

Independent DIY troubleshooting. Prefer Microsoft and OEM support articles for model-specific steps. We do not sell one-click fix tools or host driver packs.