If your computer doesn’t boot up properly then the first step should be to identify the source of the issue. Was the computer working properly before? Did anything change prior to this issue occurring? Is the power cord securely plugged in and the socket turned on? Does the power light come on when you hit the power button? All of these factors can help to diagnose the issue.
If the power light is on and nothing happens after pressing the power button, the first thing to try is to remove the battery, wait a few seconds, and then reinsert the battery. This can sometimes help to clear any overclocking settings that may have caused the issue. If this does not help, check if any debris or dirt has blocked the fan vents which could be causing the system to overheat and shut down.
Another possible issue could be a faulty hard drive. If the computer is not showing any signs of life then it is possible that the hard drive may need to be replaced. To diagnose this issue, you can remove the hard drive and connect it to another computer to see if it works. If the hard drive is functional, then the problem lies elsewhere in the system.
If the power light is on but nothing appears on the screen, then it is likely that the issue is with the monitor, the graphics card, or the cabling. The most common cause of this type of issue is a faulty or loose cable. Check all of the cables connected to the system, as well as the monitor, for any problems. If all of the cables are secure and functioning correctly, then it is likely that either the graphics card or the monitor itself needs to be replaced.
If the computer is powering up but failing to load the operating system, then the issue could be a corrupt bootloader or a corrupt Windows installation. To diagnose this issue you will need to access the BIOS and attempt to boot from a Live CD or USB stick. A Live CD is an operating system on a disc or USB drive which can be used to run diagnostic tests and troubleshoot a system. Once you have booted into the Live CD, you can then use it to repair any corrupt Windows files or reinstall your operating system.
Finally, if none of the above solutions work, then the problem may be more serious than initially thought. In this case, it is recommended that you contact a qualified technician who can diagnose and repair the issue.
In conclusion, if your computer isn’t booting up properly, then there are a variety of issues which could be the cause. To correctly diagnose the problem, you should check all of the cabling, check for any dirt or debris blocking the fan outlets, and also boot from a Live CD to attempt to repair any corrupt system files. If all else fails, it is best to seek the assistance of a qualified technician.