Windows 10: Reinstall Win 10 upgrade after HD reformat

The original OS on my PC was Win 7 Pro. I upgraded to Win 10-Pro a while ago with the free upgrade path. I was having trouble with the PC running very slowly and was told by the manufacturer that it was probably because the HD was dying. I don't think it is, but to give the PC its best chance I decided start out afresh, so reinstalled Win7 from the original CD supplied, spent 2 days with Windows update to get Win 7 'up to date' and updated all the drivers I could. and then tried to upgrade again. Unfortunately it now asks for the product key. I used the original Win 7 product key (worked last time) but this now no longer works. I tried using the Win 10 product key that I got off a Belarc Advisor report I ran before reformatting the HD. That doesn't work either. I know this is well past the deadline for upgrade, though I upgraded a couple of other PCs about 3 months ago without difficulty. Any suggestions on what I can do?

Also I have errors showing in Device Manager saying driver not installed for SM Bus Controller and USB Controller. The PC has both USB 2 and USB 3 ports. The USB 2 work but the USB 3 have stopped working.

PC is quite old (2012) but still working reasonably. The Win 7 reinstall has dealt with the speed issue I had previously.

Thanks

current Win ver: Win 7 Pro ver 6.1 (Build 7601: Service Pack 1)

:)

 

win 10 to pro upgrade reinstall

Purchased Win 10 Pro upgrade from MS store. HD crashed. Reformatted HD. Can't figure out how to reinstall Pro upgrade.

 

Fresh Install of Win 10 without Serial Key?

Looking to reformat a laptops HDD, and then reinstall Win 10 fresh. The problem is it came pre-installed with Win 8 and I did the free upgrade to Win 10. How exactly would I re-format the HDD, reinstall Win 10 and ensure it reactivates properly? I don't see a Win 8 serial key anywhere in the contents of the box.

 

Can I reinstall Windows 10 "free upgrade" version, after a HD failure?

I have a computer that the hard drive failed in, that was running the free Upgrade version of Windows 10. That computer was running Windows 7 Pro, which I still have the original disk and licence for. I upgraded to Win 10 on that computer, when it first
was offered as a free upgrade.

Is it possible to replace the HD and somehow do a Windows 10 basic "clean install" and continue to use this computer? I'm not replacing any other hardware.

I don't have the Win 10 download files, if there ever were any, and even if I do, they are on the now-dead HD.

And, I can't remember if the free download version just used my valid Win 7 licence for the valid install of Win 10.

I checked my Microsoft account, and it does not list that now-dead PC as a device. I may not have registered it when I did the upgrade.

Anyway, can someone help me? Is this possible to continue to use the free upgrade Win 10 that I had, on the new HD/old computer setup?

Do I just use my old Win 7 licence to activate the new install? Where can I download the version of Win 10 that matches the "free download" version, if possible.

Any help would be appreciated. Perhaps a link to someone who has had the same trouble, with step by step for the "new" install.

Thanks for your help!