Win 8.1 is using boot files from USB when booting Windows

[Windows Central Question]

I have had some problems with my windows 8.1 installation. It all started when I tried to update to windows 10. It failed and if I remember correctly my computer showed blue screen of death when I restarted it afterwards. Pretty sure the error code was 0xc0000034. I tried a lot of things to restore the boot files and somehow I think I have managed to have the windows installation use the boot files on my USB installation media instead of the original from drive C, where my windows 8.1 installation is found. I can only start windows with the usb inserted and when secure boot is disabled in BIOS legacy only is used.

I can't even reset windows with or without the USB installation media inserted.

I am very confused on how to proceed to fix the problem or make a clean installation (if I boot from the usb installation media, I just start windows as the boot files from the usb is used to boot windows).

I am not sure on what to elaborate, so please ask if you need any more information on the problem I am experiencing.

By the way - going to command prompt and trying to /fixmbr /fixboot etc. does not work, as it uses the directory X:\windows\system32> instead of the C: drive where windows is installed. I have probably made this change myself some weeks ago, trying to fix the 0xc0000034 error

 

[shmsnh]

If you are able to use Windows, you should try sfc /scannow in Command Prompt (Admin). This should fix any problems with the Windows installation.

How did you create the boot USB drive? If you want to continue using Windows 8.1, you should be able to download a fresh copy from Microsoft and create a bootable USB drive. If you want to use Windows 10, same process. Either way, it will be a fresh install. And in your motherboard settings, you can use either UEFI+SecureBoot or legacy BIOS, but in both cases, you will need to boot from the USB drive when going for the fresh install.