New hard drive and windows installation question

I'm pretty sure my hard drive is shot. See Thread

My problem/question:

It had windows 8 installed. About a year ago, I did the free upgrade to Windows 10. I just made an installation flash-drive for the new Windows.

I still need to buy the hard drive, but when I replace it:

1. Do you think I'll have to pay for it because it's a "new" installation?
2. Is there a key I need (can use) from my current setup?
3. Will I have to install Windows 8 first then upgrade to 10 again?


From the sound of it a hard drive change shouldn't make Windows think it is a different computer so the license should still be good. Even if it did, there is apparently a process in the Activation -> Troubleshooting wizard to inform Microsoft that you changed hardware recently and tell them which computer it is to fix activation. I think you should be good in this case.

Notably, while researching this, I discovered that if you upgraded a retail copy of Windows then you cannot reinstall the old retail copy and upgrade again. You'd have to buy a license for Windows 10 in that case. Alas, I have no real interest in running any Windows so my Windows 7 license can remain on the shelf. :P

It does sound that it might apply to you since you upgraded Windows 8. You're going to be replacing the hard drive with Windows on it, so presumably you'll have to reinstall from a disc. In that case, you may have to buy a new license to get Windows 10... But I'd do a little research before I succumbed to that. Maybe you could use the "hardware change" wizard thingy mentioned above to get Microsoft to allow the upgrade again?

Worst case, you could always try calling Microsoft support and asking about it.

Eric Johnson

I fix computers part-time as a side job. I had a client sometime last year who had his HDD die. Just like with you, he had Windows 8 and upgraded to Windows 10 for free. What I did was installed a new HDD, then installed Windows 10 on it. I used the same product key from his Windows 8 license and it worked for 10. As I recall, the Windows 10 free upgrade is tied to your MAC address and some combination of hardware, but not the HDD. So you can safely replace the HDD and keep the free upgrade so long as you have the original product key for the OS prior to the free upgrade (Windows 8 in his case).

So do this:

1. Install a new HDD
2. Install Windows 10 on the new HDD
3. Use the product key from Windows 8 for Windows 10
4. Enjoy Windows 10

This might not work if you also change your motherboard, mind you. But even in the unlikely even that your product key does not work, there are ways you can use Windows 10 without activating it. Though I leave that to you... ;)


I believe you can find the product key in the registry, if not in the system info... If not, I'm sure there's a hack tool out there to do it (but beware binary code). Google will find something.

Samuel Henderson

Another option is to just purchase a new key:

I've purchased 2 keys from here:

For ~$15 USD. So far I haven't had a problem with them.

Chris Katko

That's sketchy as hell and your key may be invalidated in the future. Windows keys are expensive as crap (except for their $10 upgrade to 10 promotion.) $100-$150.

Aaron Bolyard

I've used this tool in the past to retrieve license keys when I used Windows:


The Product Key is on the settings/about page. Is that not the correct one?

Aaron Bolyard

That's not the license key you enter during installation/activation, it's a different thing.

Eric Johnson

The key is also sometimes found in sticker form affixed to the computer itself, usually on the bottom.


I was able to install the OS and bypass key registration. Then when it was installed, I only had to logon to my Microsoft account to activate the OS.

I no longer get the "Boot manager missing" error, but the mis-matched checksum error. I replaced the CSOS battery and keep getting it. Though not all the time.

Not sure what to do at this point.


Run chkdsk

Also, if the reinstall didn't make your drive GPT, I would try out SpinRite.

I suspect your drive is failing.


No, new drive is installed. Old drive taken out.


RMA the drive.


Do you have another computer to try the drive in? Might not want to boot Windows on it in case you screw up the licensing, but boot a Linux distro or something and test the disk that way. Might help to confirm the disk is the problem.

Bruce Perry
bamccaig said:

I discovered that if you upgraded a retail copy of Windows then you cannot reinstall the old retail copy and upgrade again.

Do you have a link for that?

Maybe the problem is that there's no upgrade tool available any more (though that wouldn't only affect retail copies surely), but you can at least install Windows 10 directly (using a legally downloaded ISO or whatever MS provides) and then activate it using your retail 7/8/8.1 product key.

See Question 2 here for example.

Thread #616871. Printed from