Most common LAPTOP hardware problems.

Note. Many of these problems and solutions also apply to desktop computers.

Problem 1: No Power


When you plug the AC adapter into a laptop, there are no lights turning on at all. When you push on the power button, nothing happens. The laptop appears to be completely dead, makes no sounds, no indications of life.


Possible causes:

– The AC adapter failed and the battery has no charge left. In this case test the AC adapter with a voltmeter. If it’s dead, replace it with a new one.
– DC jack failed and the motherboard doesn’t receive any power from the adapter. In this case the DC jack has to be replaced.
– Motherboard failed. The motherboard has to be replaced, if it’s not too expensive. At times, there are some small ICs that can be tested and replaced by a technician. Otherwise get ready to buy a new computer.



Problem 2: Blank Screen


The laptop turns on, power LED lights up, cooling fan works but nothing appears on the screen. The screen is completely black and blank. There is no image on the screen at all.


Possible causes:

– This can be memory failure. It’s possible one of the memory modules failed. In this case you can try reseating memory modules to make sure they are making good contact with the slot. You can try removing memory modules one by one and test the laptop with only one module installed. You can try replacing memory modules.
– If reseating/replacing memory doesn’t help, try removing the hard drive, DVD drive, modem, wireless card, keyboard, etc… In other words, disassemble the laptop to bare minimum and test again.  

- The CMOS (BIOS) battery may be dead. In a laptop you may have to consult the owner’s manual, or Google the location of the CMOS battery. Test it with a volt meter or just replace it (they only cost a few dollars). After replacing the battery you will have to go into BIOS and redo all the settings. In most cases, load the defaults, change the time and date and you should be done. Save and exit.

- If the laptop still doesn’t turn on, most likely you have failed motherboard or processor.





Problem 3: Laptop turns off and on repeatedly


The laptop turns on without showing any image on the screen. After a few seconds it turns off by itself. Then it turns on and off again.


Possible causes:

- Most likely this is motherboard failure. You can try reseating/replacing memory as I described in the Problem 2. If it doesn’t help, probably the motherboard failed.



Problem 4: Laptop makes noise while running


The laptop turns on and everything works fine, except it makes some constant weird grinding or rattling noise.


Possible causes:

- In most cases this noise is coming from the cooling fan or hard drive. Take a closer look at the cooling fan.

- If the fan doesn’t spin but the laptop makes noise, probably it’s coming from the hard drive. Back up all personal data as soon as possible and replace the hard drive.

- Also, you can remove the hard drive and start the laptop. If the laptop still makes noise, most likely its bad fan.



Problem 5: Laptop shuts down or freezes

Possible causes:

- Most likely this is heat related issue. It happens because the fan heat sink is clogged with dust and the processor not cooling down properly. Cleaning the fan and heat sink from dust should fix it.


Problem 6: Battery not charging properly

Possible causes:

– Failed battery.  If it doesn’t charge completely try reconnecting the battery first. Also, try running the laptop just from AC adapter with battery removed. If it runs fine from AC adapter, most likely it’s either bad battery or failed motherboard. Try replacing the battery first.

– Failed DC power connector. If the battery charges only after you adjust the position of AC adapter tip inside the connector, most likely this the DC jack failed.


Problem 7: Screen does not light up

The laptop starts properly but after a while the screen light turns off. The image still appears on the screen but it’s very dark. In some cases the screen light never starts and all you can see is a very faint image.



Possible causes:


- Most likely it’s either failed screen inverter or backlight lamp (CCFL) failure.  When either one fails, the backlight stops working.

In order to troubleshoot this, you’ll need some spare parts: either new working inverter or known good backlight lamp. Open the screen housing and substitute the lamp with a spare. If the lamp works, you need to replace the lamp in the display or replace the LCD panel, if it does not work, you need to replace the inverter.



Problem 8: Strange or garbled image on the screen


The laptop turns on properly but has a distorted or garbled image on the screen.


Possible causes:

– The graphics chip failed. First of all, test your laptop with an external monitor or TV. If you see the same garbled image on the external screen, most likely the graphics chip failed.
– If the problem appears only on the laptop screen, this can be related to one of the following: poor connection between the video cable and motherboard or screen. Also can be failed video cable or LCD panel.



Problem 9: Some keyboard keys stopped working


Possible causes:


- Most likely the keyboard failed and they are not repairable. Replace the keyboard.

- If the keyboard does not correct the problem, the keyboard driver IC on the motherboard has gone bad, or the connector on the motherboard for the keyboard has gone bad. A USB keyboard can be used, or the motherboard repaired or replaced.




Problem 10: Keyboard has missing or broken keys


Problem solution:


- If a key separated from the keyboard, it’s still possible to fix it. Keycaps can be pressed back into position if they are not broken. If they are broken, at times parts can be ordered or used parts can be implemented to repair the key.
If you have many keys missing, probably it makes sense to replace the whole keyboard.





Problem 11: Repetitive beeping sound on start-up

You turn on the laptop but there is no video on the screen. Instead, it starts making repetitive beeping sound. In some cases you can “fix” the problem temporarily if you press on the keyboard keys.

Possible causes:

- Most likely you have stuck keys. In this case you’ll have to replace the keyboard.

- If the beeping is in a pattern, such as one long and two short beeps, then you have a hardware error. The beep code will have to be looked up to discover what hardware is causing the problem.



Problem 12: Computer won`t load Windows but keeps rebooting in a loop. There may be a blue error screen between reboots.


Possible causes:


- Try booting Windows into the diagnostic menu (tap F8 key while the computer is starting, keep tapping until the diagnostic menu comes up). Select “use last known good configuration” and let the computer boot. If this does not correct the boot-loop....


- Use the “Restore to a previous date” option in the “repair my computer” option in the diagnostic menu. Restore the computer back to a date when it was working.


 - The SATA Hard Drive Mode setting in BIOS may have changed. The options available  for the setting can be any combination of the following: IDE, Compatibility Mode, AHCI, RAID, or SATA. Take a note of what the setting is currently, and then try each of the other settings one at a time. Reboot the computer each time you change the setting. Tell windows to boot normally. If none of these settings corrects the boot-loop issue, change the setting back to where it was. More in-depth troubleshooting will be required.


Problem 13: Liquid Spill

You spilled something on the laptop and it’s stopped working.

Problem solution:

- Liquid spills are very dangerous and unpredictable. Turn off the laptop ASAP, remove the battery and do not use it until all internal parts are inspected for liquid damage.
It’s still possible to make it work again. Take it apart immediately. If it was just water, put the wet parts in with some rice to absorb the liquid. A hair dryer can also be used to heat up the board and evaporate the liquid. It is important to do this ASAP. If left too long, the liquid will cause the parts to corrode.

- If the liquid was not water, I would suggest bringing it to a tech shop right away. If the liquid dries on the motherboard, it most likely will never work again.


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