Laptop powers up but nothing appears on the screen

[dunalfu2]

My HP Elitebook 840 G3 is powers up when I press the power button and all the lights turn on but nothing is being displayed on the screen. I tried hard reset but it did not work.

[ZBoost_Ultra]

Hello @dunalfu2 

If your EliteBook 840 G3 powers on (lights + fan) but the screen stays black, here are the steps you should try-this model is known for a few common causes (RAM, display cable, BIOS freeze).

✅ 1. External Monitor Test (First Priority)

Connect an HDMI display.

If external works → LCD panel or display cable is faulty.

If external is also black → BIOS, RAM, or motherboard issue.

✅ 2. Perform a Real Hard Reset

This model requires removing power fully:

Turn off laptop

Disconnect AC charger

Disconnect main battery (internal - bottom cover removal required)

Hold power button 20 seconds

Reconnect battery + AC

Try to power on again

(This clears embedded controller + BIOS state.)

✅ 3. Reseat or Swap the RAM

The 840 G3 often shows a black screen from bad or poorly seated RAM.

Remove bottom cover

Remove both RAM sticks

Test with:

One stick at a time

Each slot separately

If it boots with only one stick: → the other module or slot is bad.

✅ 4. BIOS Recovery

If the BIOS is corrupted, the system powers on but shows no display.

Try this:

Turn laptop off

Hold Windows + B

While holding, press Power

Keep holding Windows + B for 10-15 seconds

Wait for BIOS recovery screen

If the BIOS recovery screen appears, let it update.

✅ 5. Check for Display Backlight

Shine a flashlight at the screen at an angle.
If you see faint graphics → the backlight or cable is bad.

Cable wear is common on older 840 models.

❗ If none of the above work

The most likely remaining causes:

Failed motherboard / GPU

Failed LCD panel

Damaged LVDS/eDP display cable

Hope this helps!