No-Video Desktop Troubleshooting (Step-By-Step)

This step-by-step troubleshooting process is for a desktop PC that powers on but shows no video output, including blank screen, no signal, or no BIOS/POST display. It begins with basic hardware checks and advances to deeper diagnostics involving GPU, RAM, BIOS/CMOS resets, firmware compatibility, and potential motherboard or CPU issues methodically evaluating every potential cause.

PHASE 0 — Define the failure clearly (don’t skip)

Before touching anything, confirm:

☐ System powers on
☐ CPU fan spins
☐ Case fans spin
☐ No BIOS splash
☐ Monitor shows “No signal” / black screen

If nothing powers on, this is a power-on problem, not a no-video problem — stop here.

PHASE 1 — Eliminate monitor & cable issues (fast + critical)

1. Confirm monitor works
   • Test monitor + cable on another system
   • Or test a known-good monitor on this system
2. Correct input selected
   • HDMI ≠ DisplayPort
   • Auto-input often fails on POST
3. Use one cable only
   • No adapters
   • No KVM
   • No docks

☑ If still no video → continue

PHASE 2 — Determine where video should come from

This step prevents chasing ghosts.

A. Check CPU model

• CPU with iGPU → motherboard video ports may work
• CPU without iGPU (KF / F / Xeon) → motherboard ports will NEVER work

☐ If CPU has no iGPU → you MUST use a discrete GPU
☐ If CPU has iGPU → GPU can be removed for testing

PHASE 3 — Strip system to minimum POST state

Remove all non-essential parts.

System should contain ONLY:

• Motherboard
• CPU + cooler
• ONE RAM stick
• GPU (ONLY if CPU has no iGPU)
• PSU

Remove:

• SSDs / HDDs
• USB devices
• RGB hubs
• Front panel USB (leave power switch only)

This removes 80% of silent POST failures.

PHASE 4 — Power connections (MOST COMMON FAILURE)

Do not assume anything is connected correctly.

1️⃣ CPU power (EPS)

☐ Correct cable: CPU / EPS, not PCIe
☐ Fully seated 8-pin (4+4)
☐ Optional secondary CPU power connected if available

⚠️ A missing or wrong CPU cable causes:

• Fans spin
• LEDs light
• NO VIDEO
• No beeps

2️⃣ GPU power (if present)

☐ All required PCIe connectors attached
☐ No loose pins
☐ Avoid daisy-chained connectors if possible

3️⃣ 24-pin motherboard power

☐ Fully latched
☐ Reseat it (don’t trust appearance)

PHASE 5 — Clear firmware state (mandatory)

This removes:

• Bad CPU undervolts
• Bad RAM training
• Wrong GPU priority
• Broken BIOS settings

CMOS reset

1. Power off PSU
2. Unplug from wall
3. Remove CMOS battery
4. Wait 10 minutes
5. Reinstall battery
6. Power on

☐ Do NOT skip this step

PHASE 6 — Memory sanity check

1. Use ONE stick only
2. Use motherboard-recommended slot (often A2)
3. Reseat firmly
4. Try each stick individually if more than one

Bad or badly seated RAM can block video before BIOS.

PHASE 7 — GPU sanity check (if required)

If CPU has no iGPU:

1. GPU in top PCIe x16 slot
2. Reseat GPU
3. Confirm PCIe latch clicked
4. Try different GPU if available

If CPU has iGPU:

• Remove GPU completely
• Use motherboard video output

PHASE 8 — Firmware compatibility (silent killer)

Common with:

• New CPUs
• New GPUs
• Older motherboards
• First-revision boards

☐ Board may POST electrically but fail to initialize video

Solutions:

• Update BIOS
• Use BIOS flashback / Q-Flash / USB Flash if no video
• Use older known-compatible GPU temporarily if needed

PHASE 9 — Look for POST feedback

Check for:

• Debug LEDs
• Beep codes (attach speaker if possible)

Patterns matter:

• Stops on CPU → power / socket / BIOS
• Stops on DRAM → RAM or IMC
• Stops on VGA → GPU or BIOS init

PHASE 10 — Advanced (only after everything above)

☐ Inspect CPU socket pins
☐ Reseat CPU
☐ Remove board from case (rule out short)
☐ Breadboard on cardboard box

Frequent causes of no-video (memorize these)

• Missing CPU power = no video
• Wrong cable = same result
• KF / F CPU = motherboard ports useless
• Bad BIOS = GPU never initializes
• Fans spinning ≠ system POSTing

Final Tips

Never troubleshoot by assumption.
Always troubleshoot by elimination.