HP ProBook 640 G5 Does Not Power On

If the power button or its internal cable is damaged, the laptop may not respond when the button is pressed. Over time, the button mechanism can wear out or the internal connector may become loose, preventing the signal from reaching the motherboard.

Solution

Press the power button several times to check if it feels stuck or unresponsive. If the button does not click normally or requires excessive force, the internal switch may be damaged.

You can also test whether the laptop powers on by briefly disconnecting and reconnecting the internal battery or AC power to see if the system responds.

If the power button assembly is faulty, it may need to be replaced.

Follow this repair guide to replace the power button:

HP ProBook 640 G5 Power Button Replacement

Laptop batteries degrade over time and may eventually lose the ability to hold or deliver a charge. A fully depleted or damaged battery can prevent the laptop from powering on.

Solution

Make sure you are using a charger that has been confirmed to work on another device.

Connect the charger to the laptop and allow it to charge for at least 15-30 minutes before attempting to power it on again.

If the laptop still does not power on while connected to power, the battery may need to be replaced.

Follow this guide for battery replacement:

HP ProBook 640 G5 Battery Replacement

Improperly seated or damaged RAM can prevent a laptop from completing its startup process. In some cases, the device may appear completely unresponsive if the memory is not functioning properly.

Solution

Listen for repeating beep patterns or watch for blinking lights on the Caps Lock or Num Lock keys, which can indicate a RAM failure.

Power off the laptop and disconnect the charger. Open the bottom panel and locate the RAM modules.

Remove the RAM sticks and reseat them firmly in their slots. If the problem continues, test the laptop with one RAM module at a time to identify a faulty stick.

Follow this guide to access the internal components:

HP ProBook 640 G5 RAM Replacement

A malfunctioning keyboard or a stuck or damaged power button located on the keyboard deck can prevent the laptop from turning on. If the power button key is not sending a proper signal to the motherboard, the system will not respond when you attempt to start it.

Solution

Inspect the keyboard and power button area for stuck, unresponsive, or physically damaged keys. Try pressing the power button repeatedly to check if it feels loose, jammed, or inconsistent.

If the laptop powers on intermittently when applying pressure near the power button, the keyboard assembly may be failing and require replacement.

Follow this guide to replace the keyboard:

HP ProBook 640 G5 Keyboard Replacement

In some cases, the laptop may actually be powering on, but a faulty screen makes it appear completely dead. A damaged display panel, backlight failure, or disconnected display cable can result in a black screen even if the system is running.

Solution

See if there is power to the laptop by pressing the power button and listening for fan noise, look for keyboard lights, or LED indicators. If these activate but the screen stays black, the issue is likely the display rather than the power system.

Connect the laptop to an external monitor using HDMI or DisplayPort. If the external display works normally, the internal screen or display cable likely needs repair or replacement.

Follow this guide to fix the display:

HP ProBook 640 G5 Display Replacement