Computer won't turn on

If there is a IT hotline in your city, call it. They will provide you with the right solution to your problem and if possible they will tell you how to solve it by yourself.

Check if all the cooling fans in your computer (or the cooling fan in the laptop) are working properly. There is a fan on the CPU, some graphic cards, in the power supply and in the computer case.

The purpose of the cooling fan is to provide a good airflow so that all the componets can work properly. 

If a cooling fan is not running at all (especially those on the CPU and the graphic card), then it's possible that your computer is overheating and it doesn't boot (turn on) due to the built-in safety mechanism designed to prevent severe hardware damages.

If your computer is no longer under warranty, you can take it to a computer repair store. The repair team will diagnose and solve the problem.

If you have recently bought your computer or laptop and it doesn't turn on, a factory defect may be the problem. Go to the computer store where you bought it and enclose the receipt you received and they will replace the computer with a new one.

It is possible that the power outlet where your computer's power cord is plugged in is not working properly. To check this, disconnect the computer's power cord and plug another device in the same outlet or test the outlet with a mains tester CAREFULLY.

• If the device is not working properly as well, then the outlet is broken and plugging the power cable in a different power outlet should solve the problem.

• If the device is working properly then another thing may be preventing your computer from turning on. Check another of the solutions listed below.

Note: Do not buy cheap outlets because they may start a fire due to their weak insulation.

If you notice a strange smell of something burnt coming out of the computer case it is possible that the power supply is broken. This is usually a result of a faulty power outlet, or a weak power cord. Replacing the power supply will enable you to turn your computer back on. 

 Also, if your computer turns on and immediately turns off, the power supply might be broken as well.

Note: Do not replace the power supply on your own. Also, before turning your computer on, call an electrician to examine the power outlet because it may have caused the problem in the first place.

If you recently added a new hardware (e.g. a new RAM memory stick, hard disk drive, graphic card etc.) to your computer or replaced an old hardware component, remove it from the computer in order to check if that is the culprit that prevents your computer from turning on.

If the computer does turn on, either the new hardware component is broken or it is incompatible with other hardware components of your computer.

As time goes by, the power cord weakens and it doesn't provide a good flow of electricity between the power outlet and the computer.

Unplug the power cord (the cord which connects the computer's power supply and the power outlet, or the cord that connects the laptop's adapter and the power outlet) and examine it carefully. If the power cable is damaged (e.g you saw a blue, yellow-green or black wire, or copper), replace it. 

Maybe the power cord doesn't have visible signs of damage. Try plugging a different power cord in a power outlet which is working properly. If your computer does turn on, your power cord is the problem and you should replace it.

Also, you can check the same power cord on another computer, or other device that requires the same power cord type and are working properly. If that device doesn't turn on as well, the power cord is the problem and you need to replace it.

Note: Buy a thicker power cord because it is far better insulated and less prone to physical damages. Electricity is not a toy you can play with and it is very important to buy a high-quality power cord, which is thicker (because it has a better insulation). A low quality power cable may cause a severe computer malfunction such as inflicting a damage to a computer component (usually the power supply). Furthermore, keep the power cable from direct sunlight exposure and hot environment.

Sometimes, a loose power cable can be a reason why your computer doesn't turn on. Check if the power cable is properly plugged in and make sure it is not loosely connected.

A loosely connected cable prevents a good flow of electricity and that is why you should be very careful how you plug it in.

Test the power outlet where your computer is plugged in. If you are not sure how, check this article.

If there is no electricity, check if there is any electricity in another power outlet in the same room or in the house/flat. If there is, try and plug in the power cord there to see if the computer turns on then.

Note: BE VERY CAREFUL WHEN YOU TEST THE POWER OUTLET. EVEN A MINOR CONTACT OF TWO OF THE WIRES IN THE OUTLET MAY RESULT IN SEVERE INJURIES.

Maybe faulty or damaged hardware component prevents your computer from turning on. It may be the power supply, the motherboard, (one of) the RAM memory stick(s), the graphic card, the hard disk drive, a broken data cable and etc.

The difficult part is locating the right culprit and that is why every hardware component need to be tested separately.

Unless you know how, it is wise to call a IT repair guy who will find and replace the bad hardware component. If you feel that you can troubleshoot the computer check out this article, which should guide you if you need help.

It may be the laptop's battery that prevents your laptop from turning on. Try turning your laptop on directly through the AC adapter (remove the battery first). If it does turn on, then it is the battery itself that needs replacement.

Note: Buy a new and unused battery only. They usually last for two to three years (depending on the manufacturer). Also, it may last longer if you use it only at places where you don't have access to electricity, or if you are at home, you can connect your laptop to the adapter and remove the battery. 

Check inside the dektop computer case to see if the power supply cables are firmly connected to the motherboard. If you notice a loosely connected cable, plug it back in firmly because without a good electricity flow to the motherboard, your computer won't turn on. 

Note: If you don't know how to do that, this useful video might help you:

It is possible that the laptop's AC adapter is the problem. Plug it in a power outlet and connect it to the laptop.

If the AC adapter's green light isn't glowing and the laptop's battery isn't charging, the AC adapter needs replacement.

Note: AC adapters aren't universal, so make sure to take the old adapter or the laptop itself with you so that you buy an appropriate replacement. Do not buy old adapters, because you risk damaging the laptop.

Maybe one of the external devices connected to your computer has malfunctioned. Remove any CDs, DVDs, USBs and other external devices (such as portable HDDs) that are connected to the computer. Then turn the computer on and check if it starts normally.

If it does, start returning the external USB devices one by one so that you find the faulty one.

Check if everything is correctly inserted in the motherboard. If there is a component (hard disk, RAM memory, CPU, graphic card, etc.) that is not inserted correctly on the motherboard your computer won't boot up until you reinsert the component properly.

Also, you can check the voltage regulators which can be found near the CPU, memory slots, chipsets and other parts to see if they are fried. If they are, you might notice a little bump on top of them. In that case, you should go to a computer repair store to have it replaced.

If you still want to try diagnosing the problem, this Youtube video might help you: 

Check if the RAM memory stick(s) on the desktop computer/laptop is (are) inserted in the RAM slot(s) correctly and in the correct slots (according to the motherboard's manual). A faulty or incorrectly inserted RAM memory stick(s) may prevent the desktop computer/laptop from turning on. 

If you don't know how to remove and insert RAM sticks, read these useful article:

Laptop (by Dummies) or Desktop computer (by Howtogeek).

If you recently added a new CPU on your computer, check if it's correctly inserted. Try to remove it and reinsert it again in the socket.

Also, you need to reapply a fresh thermal compound between the CPU and the heatsink once you put it back into the socket or if it the thermal compound hasn't been reapplied for a long period.

If you are not sure how, watch this video:

If you use a desktop computer that has a video card which is not integrated in the motherboard, check if it's inserted correctly. Also, check if the VGA cable (the cable that connects the montior and the computer) is inserted correctly in the video-card slot. If it is inserted correctly, then the problem might be the graphic card itself. 

Also, there is a specific beep code which tells you if the graphic card is not working properly. To find out how to identify the beep code, click here

Also, you can read this article to find out more about the 6 signs that your graphic card is dying.

Maybe your computer is on, however it doesn't show anything on the screen because the monitor is switched off. Solution: Switch it on! :-)

Also: Check the VGA cable (the cable going into your monitor) if it is misplaced. 

Maybe there is an issue with your battery. Remove it, and start the laptop with only the power cable plugged in. 

Mabye your computer does turn on, but there are issues with your screen/monitor. Check out the Screen is blank solutions. 

Maybe the power on/off button has malfunctioned and that is why your computer doesn't turn on. Replacing the power on/off button will fix the issue.

Maybe the new RAM stick you added is incompatible with the one which is already inserted in the computer. If this is the case, all you need to do is take your old RAM to a computer shop and ask them for a compatible RAM stick.

Note: If you didn't manage to find a compatible stick with the old one, consider buying a RAM stick set.

Maybe there is something wrong with the computer's CMOS settings. In this case, all you need to do is to reset the settings and after that your computer should start working.

These are two common ways of clearing the CMOS settings:

1. Via the CMOS jumper
   
   Turn off the computer and unplug it from the power cord. Then, open the computer’s case and locate the jumper named in one of the following ways: CLEAR, CLR CMOS PASSWORD, CLR PWD, CLEAR CMOS, etc., most often located near the CMOS battery. Then, unsit the jumper from the current position and set it to “clear” position. Then, turn on the computer and turn it off after a short period of time, and after you turn it off (and unplug in from the power cord), reseat the jumper into the original position.
   
   This is how a jumper looks like:
   

   
   
   
   * Not all motherboards have clear-CMOS jumpers.
   
   

2. By reseating the CMOS battery
   
   The CMOS battery is the one which provides the power used to save the BIOS settings (among which time and date). So, all you need to do is to remove the battery and reinsert it after a minute or two and the CMOS settings will be cleared. Be very gentle when removing the battery in order to avoid damaging its socket.
   
   

   

   
   * Not all motherboards have removable CMOS batteries. If the battery won’t come loose easily, don’t apply force to remove it.

if the RAM slots is clogged with dust, the motherboard won't be able to recognise the RAM stick. All you need to do is to clean the RAM slot and then reinsert the RAM again.