How to fix a computer that turns on but does not start Windows 10?

Beware of the EFI boot that is sometimes damaged, or after an update of the system, it is necessary to launch windows in repair mode and repair this boot (unfortunately you need to know a little about the subject).

Repairing an EFI boot loader on a GPT hard drive for Windows 7, 8, 8.1 and 10 on your Dell desktop computer

If, at boot time (after reboot), some keys (related to the brand/version of your Windows and your PC like ECHAP/SUPPRIM/F2,F8,F9,F10,F12) do not allow to boot Windows in repair mode and restore the operating system “without erasing data”, You need to make a bootable USB key or an external repair disk with another PC. A version of Windows 10 USB to reinstall your PC is available for free on the Microsoft website or on the website of the brand of your computer (windows OEM version). Use USBIT to make your key from the downloaded image. Then boot on this key in order to repair or reinstall Windows without deleting data (if the hard disk is not broken, otherwise same procedure but after replacing your hard disk by a new one, preferably a 256Gb, 512Gb or better 1Tb SSD disk).

All the procedures for booting into safe mode and repairing and restoring and downloading images of Windows are available on the Microsoft site and other computer experts.

Indeed, it is quite vague. Are you able to boot with an installation key, for example, of Linux, or of WIndow, made on another computer? Are you able to access the configuration screen for disks, memory, boot, etc (also known as BIOS)? Do you have an error number displayed on the screen?

If you can boot from a USB stick, are you able to see your hard drives that you know are in your computer?

To me, the two most likely things are:

  • A defective hard drive
  • An installation of Windows that has gone haywire

In both cases, you should be able to boot from a USB stick (or CDROM) with something like a Windows installation key – or even better: Linux.

I have often rescued failed hard drives by booting with Linux because Windows didn’t work anymore.

There are too many possibilities to take into account. That it lights up, it’s not bad.

Start by looking if the hard disk light turns on at startup. If not, you should check the BIOS, to see if it recognizes the hard disk (or SSD). In any case, it would be good to check the BIOS settings, to see that everything is in order. If it doesn’t recognize it, then you have to look for the reason.

If you have excluded these errors, then you should check the installation of Windows 10 and/or check the “health” of the disk. If it is not working, then you have to change it.

It is also possible that there is a problem with the integrity of Windows 10 files. For example, the Boot sector has jumped. Then you should reinstall, or repair with a Windows 10 installation support.

If you don’t know how to do this, get help.