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HP ProBook 4520s Troubleshooting
Laptop Will Not Power On
The laptop will not respond or show any sign of powering up.
Faulty Power Adapter
Verify the AC power adapter is plugged into the outlet and laptop. With the battery installed, press the power button. If the power indicator light turns on then turn the laptop off. Next, with the adapter plugged in, remove the battery. Press the power button. If the power indicator light doesn’t turn on, the device has a faulty power adapter.
First ensure the battery is charged. Once charged, unplug the AC power adapter while the battery is inside the laptop and press the power button. If the laptop does not turn on, remove the battery, plug in the AC adapter, and press the power button. If the laptop turns on then the battery is faulty. Replace the battery.
Laptop Won't Boot
The laptop does not load the Operating System and instead displays a blank screen or an error message.
If the laptop starts up with the power indicator light on but only displays a black screen, try the following steps. Disconnect all peripheral devices. Unplug the AC power adapter and then remove the battery. Press and hold the power button for at least 15 seconds. With the battery still removed, plug in the AC power adapter. Press the power button. If the screen still does not display, there may be an issue with the screen hardware. Power off and open the laptop. Reconnect the ribbon cable for the screen if disconnected. If the ribbon cable was connected, replace the screen.
Hard Drive Error
If the laptop suddenly shuts down without warning, it might have a hard drive error. Self test the hard drive by taking the following actions. Turn off the laptop. Press and hold the power button to turn it on and immediately press the “f10” key to open the BIOS setup window. Select the Tools or Diagnostics window. Select Hard Drive Test and then click the “enter” key to start the test. If the test indicates a problem with the drive, open the Settings menu and click Defragment and Optimize Drives. In the Optimize Drives window, click to select the drive that had the error and then click Optimize. If the problem persists, replace the hard drive.
The laptop is on but the display does not showing anything.
As a preliminary measure, perform a “dry reboot.” Unplug the power adapter, remove the battery, and hold the power button for 45 seconds. With the battery still removed, plug in the power adapter and restart the laptop. If the display shows up, no further action is needed and you may disregard the following steps.
Take the laptop to a darkened room and inspect the screen with a flashlight. If the laptop desktop can be seen with the flashlight, the laptop backlight is faulty and needs to be replaced.
Faulty LCD Display
If the above "dry reboot" steps did not work and the display was not visible using a flashlight, the LCD screen may need to be replaced.
Device Is Overheating
While in use, the laptop randomly shuts off without notification.
Place the laptop on a hard, flat surface. Avoid placing the laptop on a cloth surface, such as a bed or blanket, as it could block air intake and exhaust vents found on the bottom of the laptop.
Dust In Vents Or Fans
The laptop may be overheating if it shuts down unexpectedly and feels very hot to the touch. Clear the fan vents and air intake slots from lint and dust by using a can of compressed air. The fan vents are located on the left side of the laptop. The air intake vents are located under the left side of the keys labeled “f1-f4,” “QWERT,” and “ASDF." If this does not work and airflow still cannot be felt then clear the vents from within the laptop by removing the keyboard and blowing compressed air through the fan vent.
Graphics Driver Outdated
The graphics card may need an updated driver. Download and install the latest graphics driver and BIOS software for the laptop’s operating system version.
Keyboard/Keys Not Responding
The keys on the keyboard won't respond as expected or appear to be broken or missing.
Num Lock Key Pressed
The numlock function key may have been pressed. To turn off the numlock function, press and hold the function key labeled “fn” while simultaneously pressing the “num lock” key.
A key may be jammed if it cannot be pressed or sticks. Wipe the keyboard using a slightly damp cloth with mild detergent such as liquid dish soap. Wipe with a dry cloth. If the key still sticks, the obstruction may be underneath the key. Pop off the key and make sure nothing is below it. Clean the area under the key with a Q-tip and rubbing alcohol. Once it is sufficiently clean, snap the key back into position.
When certain keys on the keyboard can be pressed but do not respond, try the following steps. Unplug the power adapter, remove the battery, and hold the power button for 45 seconds. With the battery still removed, plug in the power adapter, restart the laptop, and log back in. Press the “esc” key multiple times. If a startup menu opens and the keys appear functional, uninstall and reinstall the keyboard software in the Device Manager. If a setup menu fails to open, the integrated keyboard hardware is faulty, replace the keyboard.
If keys on the keyboard are missing or broken, replace them.
Failure To Read CD’s And DVD’s
The laptop will not read any discs.
Discs with scratches or blemishes will be hard for the optical drive to read. Check the bottom of the disc and try cleaning it with a damp cotton rag. Dry the disc using the same cloth. If the disc is badly scratched, try using a repair kit from an electronics store.
The following steps apply if the laptop runs on Windows 8 or 10. Reinstall the driver type “devmgmt.msc” into the Run dialog box and hit the "enter" key. Go to DVD/CD-ROM Drives in Device Manager. Right-click CD and DVD devices. Click Uninstall and then click OK. Restart the laptop. The driver should automatically install when the laptop is restarted.
Faulty Optical Drive
The optical drive could be defective or broken and should be replaced.