Question Selecting proper boot device.


Jan 21, 2016

I've just returned with my PC which I had to have some work done on it due to an error in swapping over a CPU from half of a system that I bought second hand for parts.

I had to swap over all of my major components onto the motherboard of the new system that I got and am now using that as well as both my old hard drive and a new one which has been wiped for me to use as extra storage space.

The issue I'm having now that I'm at home and trying to use it is that Window's doesn't seem to be working and the message that I'm recieving from my system is "Reboot and Select proper Boot device or Insert Boot Media in selected Boot device and press a key"

I'm a complete novice when it comes to the systems behind the computers and I tried looking for answers online before coming here but couldn't find anything that worked or made sense to me. So I was wondering whether anyone here might know how to handle this situation here (it might be a lot easier than it seems to me right now) so that I can fix it myself here tonight or whether I'll need to call up the shop in the morning that just fixed all of my hardware when they're open again.

Thanks for reading and if there's any information that you need then just let me know.




Aug 21, 2015
Get to your bios during boot (depends on the motherboard but during boot try repeatedly pressing delete and f8 (or if the boot screen tells you what to press press that!). When you're in the bios look for options pertaining to boot, boot devices, or boot order. Make sure in the boot priority that the drive that has Windows installed is listed first, or at all. It should be recognized as something like Windows Boot Manager. To make absolutely sure the bios is at least looking at the right drive you could even power down, open the case, and unplug the new drive (and unplug all USB drives to make triple sure). If you can get to the BIOS and find that information, maybe tell us what you're seeing first before doing anything else. If you had two hard drives in the past when you first installed Windows it's possible the system boot partition was on the other drive, which is now gone. There are ways to repair that boot functionality, but it depends on if your disks are formatted with GPT or MBR, and stuff like that so let's hold off on that at first. Honestly it'd probably be easier to just install, if you can get to your files.

You can get a USB to SATA connector (I'm assuming you have a SATA drive), like here; - and use that to connect your old drive to any other PC you have access to (maybe a laptop, a friend's, etc.). Then you can find all your files and copy them to safety (just your files from your various libraries, not the Windows system files or program files).

It sounds like you basically have a different computer now (in particular different motherboard and cpu) and are trying to boot a hard drive that had Windows installed on different hardware. That CAN work but can also be sorta weird, and reactivating the license can also be a hassle. I think for such a big hardware change that it's worth just reinstalling windows but the preferred way to do that now is to link your Windows 10 install to a Microsoft account (even if temporarily), reinstall, then link to the Microsoft account to activate. You could search for and follow instructions for doing a clean install of windows 10 using the windows media creation tool to create a bootable USB drive. I'd recommend clean installing onto the NEW drive, so that you don't overwrite the files on the old drive. Then you can mount the old drive and have access to all your files (and either just delete all the old Windows stuff on the old drive, or copy your files to a safe location then wipe the old drive). But before you do that make sure you know how you're going to reactivate Windows. Ideally your old install was tied to a Microsoft account and you can link the new install to it, like I said. Or, you may just outright have a product key, which is great too. Are either of those two cases true?


Apr 13, 2019
That error can happen when usb is the primary boot drive (or even with a CD/DVD drive). As long as there are no usb drives with boot instructions, the bios will bypass the USB boot and move on to the 2nd or 3rd boot choice until it finds a drive with boot instructions. However, once in a while I will have a USB drive connected for some reason (or a dvd in the drive), and my computer will try and boot of it and give the error you describe.
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