PC Turns On But No Display — How to Fix It
Fans spin, lights come on, but your monitor stays black. Here's every cause and how to fix it step by step.
PC turns on but no display — what’s happening?
When your PC powers on — fans spin, RGB lights up, drives spin — but the monitor stays black, it means one of two things: the PC isn’t completing POST, or it is completing POST but the video signal isn’t reaching your monitor.
These are different problems with different fixes. This guide covers both, starting with the simplest checks and working toward the less common causes.
Before anything else: the obvious checks
These cause more “dead PC” panics than actual hardware failures.
Is the monitor cable plugged into the GPU, not the motherboard? This is the most common cause of no display on a new build. If your build has a dedicated GPU, the motherboard’s HDMI or DisplayPort output is disabled by default. The cable must go into the GPU. Check the back of your PC — the GPU ports are on the lower section of the I/O, the motherboard ports are higher up near the USB ports.
Is the monitor actually on? Check the power light on the monitor. Press the physical power button on the monitor itself, not just the PC.
Is the monitor set to the correct input? Most monitors have multiple inputs — HDMI 1, HDMI 2, DisplayPort, etc. Press the input button on the monitor and cycle through until you find the active one.
Is the cable fully seated at both ends? DisplayPort and HDMI cables can look connected but not be fully clicked in. Unplug and firmly reseat both ends.
Try a different cable. Cables fail more often than people expect. If you have a spare HDMI or DisplayPort cable, swap it and test.
Try a different monitor or TV. If you have another display available, plug into that. If it works, your monitor has a problem. If it doesn’t, the problem is the PC.
Step 1: Check where the video signal is coming from
Do you have a dedicated GPU? If yes — the cable must be in the GPU, not the motherboard. Even if your CPU has integrated graphics, the iGPU is typically disabled when a dedicated GPU is present.
Do you have integrated graphics only (no dedicated GPU)? If yes — the cable must be in the motherboard. There are no GPU ports because there’s no GPU.
Are you unsure? Look at the back of your PC. If there’s a separate card with its own ports below the main I/O panel, that’s your GPU. Plug into that.
Step 2: Reseat the GPU
A GPU that isn’t fully seated in the PCIe slot will often power on — fans spin, lights come on — but produce no video output.
- Power off and unplug the PSU from the wall
- Open the case and locate the GPU in the PCIe x16 slot
- Press the retention clip at the end of the slot to release the card
- Remove the GPU completely
- Inspect the PCIe slot and the GPU’s gold contacts for debris
- Reinsert the GPU firmly until you hear the retention clip click
- Verify the GPU bracket is flush with the case — if it’s angled, it’s not fully seated
- Reconnect all GPU power cables
Step 3: Check GPU power connectors
A GPU without adequate power will turn on partially — fans spin, LEDs light up — but won’t output video. Every required power connector must be fully seated.
Check:
- All 6-pin, 8-pin, or 16-pin GPU power connectors are plugged in
- Connectors are fully clicked in at the GPU end, not just the PSU end
- If using a modular PSU, connectors are fully clicked in at the PSU end too
Some GPUs require two 8-pin connectors. If only one is connected, the card may appear to power on but won’t function correctly.
Step 4: Reseat the RAM
RAM that isn’t fully seated is one of the most common causes of no POST and no display. The system appears to power on but can’t complete its startup checks.
- Power off and unplug
- Press the retention clips on both ends of each RAM slot outward
- Remove all RAM sticks
- Reinsert one stick firmly in the A2 slot (second slot from CPU — check your motherboard manual)
- Press until both retention clips click
- Power on and test
If it displays with one stick, try the other stick alone. If one stick works and the other doesn’t, you have a faulty RAM stick. If neither works alone but both together did before, try different slot combinations.
Step 5: Check the 8-pin CPU power connector
The 8-pin (or 4+4 pin) CPU power connector in the top-left corner of most motherboards is easy to miss on first builds. Without it connected, the system may power on but fail to POST and produce no display.
Locate the connector — it’s usually labelled CPU_PWR or ATX12V on the motherboard, near the top-left corner. Verify it’s fully seated. It requires more force than expected and should click firmly into place.
Step 6: Test with integrated graphics
If your CPU has integrated graphics, remove the dedicated GPU entirely and plug directly into the motherboard’s video output.
CPUs with integrated graphics:
- Most Intel CPUs (except F-series — Core i5-12400F, i7-13700F etc. have no iGPU)
- AMD Ryzen G-series (5600G, 5700G, 7600G etc.)
CPUs without integrated graphics:
- AMD Ryzen non-G (5600, 5700X, 7600X etc.)
- Intel F-series
If the system displays with integrated graphics but not with the dedicated GPU, the GPU is the problem — either faulty, not seated correctly, or not receiving adequate power.
Step 7: Clear CMOS
Corrupt BIOS settings can prevent POST and cause no display. Clearing CMOS resets everything to factory defaults.
Method 1 — CMOS jumper:
- Power off and unplug
- Find the CMOS jumper on the motherboard (labelled CLR_CMOS — check your manual)
- Move the jumper from pins 1–2 to pins 2–3 for 10 seconds
- Move it back to pins 1–2
- Power on
Method 2 — Remove the CMOS battery:
- Power off and unplug
- Locate the coin cell battery on the motherboard
- Remove it and wait 60 seconds
- Reinsert and power on
Step 8: Check for POST beep codes or debug LEDs
Beep codes: If your motherboard has a speaker connected, listen for beep patterns on startup. These indicate exactly what’s failing:
| Beep pattern | Likely cause |
|---|---|
| No beeps at all | No speaker connected, or CPU/power issue |
| 1 long, 2 short | GPU issue |
| 1 long, 3 short | GPU issue |
| Continuous long beeps | RAM issue |
Beep code patterns vary by BIOS manufacturer — check your motherboard manual for the exact codes.
Debug LEDs: Most modern motherboards have a row of LEDs labelled CPU, DRAM, VGA, BOOT. The LED that stays lit indicates the failing component:
- CPU LED lit — CPU issue, power issue, or incompatible CPU
- DRAM LED lit — RAM issue
- VGA LED lit — GPU issue
- BOOT LED lit — storage or OS issue
If VGA is lit, focus on GPU seating and power. If DRAM is lit, focus on RAM. If CPU is lit, check the CPU power connector and CPU seating.
Step 9: Check for motherboard standoff shorts
If the motherboard is shorting against the case, it can cause erratic behavior including no display. This is more common on first builds.
Remove the motherboard from the case and test boot on a non-conductive surface — the motherboard box works well. Place the motherboard on the box, connect PSU, CPU, one RAM stick, and GPU, and test.
If it displays outside the case but not inside, a standoff is misaligned — either missing under a mounting hole causing flex, or present where there’s no hole causing a short. Check every standoff position against the motherboard mounting holes.
Step 10: Isolate with minimum hardware
Strip the build to the absolute minimum required for POST and test:
- Motherboard
- CPU with cooler
- One RAM stick in A2
- GPU (or use iGPU if available)
- 24-pin motherboard power
- 8-pin CPU power
- GPU power connectors
- Monitor cable into GPU (or motherboard if using iGPU)
Remove everything else — extra RAM, all storage drives, all USB devices, case fans, front panel connectors except power button.
If it displays with minimum hardware, add components back one at a time until it stops. The last component you added is the problem.
Common scenarios and their fixes
| Symptom | Most likely cause | Fix |
|---|---|---|
| New build, fans spin, no display | Cable in motherboard not GPU | Move cable to GPU |
| New build, debug LED on VGA | GPU not seated or no power | Reseat GPU, check power connectors |
| New build, debug LED on DRAM | RAM not seated | Reseat RAM in A2 slot |
| Worked before, now no display | Loose cable or connection | Reseat GPU, check all cables |
| Worked before, no display after moving PC | GPU or RAM unseated in transit | Reseat both |
| No display after GPU upgrade | Wrong port or needs more PSU power | Cable in new GPU, check PSU wattage |
| No display, burning smell | Hardware failure | Power off immediately |
Still no display?
If you’ve worked through every step and still have no display, one of these is likely:
Faulty GPU. If the system POSTs and displays with integrated graphics but not with the dedicated GPU, the GPU may be DOA. Test in another system if possible, or RMA it.
Faulty RAM. Try a known-good stick from another system if available.
Faulty motherboard. If debug LEDs point to the board, or the system won’t POST under any configuration, the board may be faulty. Check for visible damage — burnt components, bulging capacitors.
Incompatible CPU. Some motherboards require a BIOS update before supporting newer CPUs. This requires a compatible CPU to perform the update — check your motherboard’s CPU support list and required BIOS version on the manufacturer’s website.
Built a new PC and still hitting problems? Check our PC won’t POST guide for a full diagnostic checklist, or our beginner build guide for assembly tips.