A computer not booting is an unfortunately common problem. The first and most important step to take in this situation is to identify the cause of the problem. Unfortunately, there can be multiple causes for why a computer won’t boot up. The diagnosis process itself can be difficult, but is essential if you hope to find a resolution.
The following sections will discuss common reasons why a computer won’t boot up and what steps should be taken to combat each issue.
1. Power Issues
The most common issue when dealing with a computer not booting is a power issue. This could include everything from a dead power supply, to a loose power cord, to a blown outlet fuse.
A. Dead Power Supply
The power supply can be tested by using a multimeter. To do this, locate the 20 or 24-pin connection on the motherboard, typically labeled P1 or P2. With the multimeter set to the DC current setting, touch one probe to the ground pin (typically black) and the other to each colored +12V lead. If the meter reads anything other than +12V, then the power supply is bad and needs replaced.
B. Loose Power Cord
If the power supply seems to be working, then it’s time to check the power cord. Make sure that the power cord is firmly connected to both the power supply and the outlet. You may need to use a voltmeter to check the outlet to make sure it is delivering the proper voltage to the computer.
C. Blown Outlet Fuse
The last thing to check is the outlet fuse. If the outlet’s fuse has blown, nothing will happen when the power cord is plugged in. You may need to have an electrician replace the fuse.
2. Motherboard Failure
If the power supply and power cord are functioning as they should, then it may be an issue with the motherboard. Motherboard failure is a common cause of computer non-functionality. This is typically caused by a power surge or electrical short.
A. Power Surge
A power surge can occur when an electrical device is switched on or off. The sudden surge of electricity can overwhelm the motherboard, leading to its failure. To check for a power surge, use a multimeter and measure the voltage across the power inputs to the motherboard. If the voltage is lower than normal, then the power surge is likely the culprit.
B. Electrical Short
An electrical short is when two separate circuits become connected, resulting in electricity flowing in both directions. This can damage components on the motherboard, leading to failure. To check for an electrical short, use a multimeter to measure the voltage on each of the motherboard’s pins. If the voltage on two or more pin pairs is higher than normal, then there is likely an electrical short present.
3. BIOS Settings
Sometimes, the issue may not be related to hardware at all. The BIOS settings may need to be adjusted in order to get your computer to boot. To access the BIOS, restart the computer and press the necessary key repeatedly as soon as it turns on. This key varies by manufacturer; for example, some Dell computers require pressing the F2 key while others may require the F9 key.
Once in the BIOS, navigate to the “Boot” tab and look for a setting called “Boot Priority” or something similar. From here, you can choose which device the computer should boot from. For example, if you have a USB drive plugged in that you want to boot from, you can select it from this menu.
4. Corrupted Operating System
If all of the above checks fail, then it’s possible that the operating system has been corrupted. This could be due to a virus, improper shutdown, or even an error with the installation. To diagnose operating system issues, you may need to boot from a disc or USB drive that contains a version of the same operating system. This will allow you to get into the system and diagnose the issue.
If the operating system appears to be functioning normally, then it’s possible the problem lies elsewhere. You may need to reinstall the operating system or restore the system to an earlier point in time. Cloning the hard drive to another drive and running the system from that might also be an option.
Conclusion
There can be many different causes of a computer not booting. The first step to diagnose the issue is to check the power supply, power cord, and outlet. If those are okay, then it could be an issue with the motherboard or BIOS settings. If those are still fine, then there may be a problem with the operating system. No matter what the issue is, there are steps that can be taken to diagnose and solve the problem.