Windows 10: Reinstall Windows 10 Product key wont work

So the last update from windows 10 caused my computer to crash so I had to reinstall Windows 10. As of right now it's showing its not activated and that it needs a product key. I still have the product key of when I first purchased Windows 10 but I get an error and it says that the product key cannot be used I need a new one. So should I purchase a new copy of Windows? Or is there an easier way to fix this I still have the original DVD and everything any suggestions?

:)

 

How to reinstall Windows 10 if my computers used the free upgrade from 7 and 8?

Will windows 10 still accept the license keys from 7 and 8 now if I reinstall my computer?

Does Microsoft keep a list of users who upgraded to Win 10 using their 7 and 8 keys so that when users need to reinstall windows 10 the old keys would work?

Do I need to call in Microsoft to ask them to activate my Windows 10 when I give them my win 7 keys?

Both computers are laptops. The windows 7 machine had the serial printed on the back, and I needed to enter that when I upgraded to 10. The windows 8 machine had the serial built in inside its boot system so I didn't need to enter the key when I upgraded to 10, but I did manage to write down the keys using a fetcher program.

 

Reinstall Windows 10 with OEM product key

When you upgraded from a previous version of Windows or receive a new computer preinstalled with Windows 10, what happened is the hardware (your PC) will get a digital entitlement, where a unique signature of the computer will be stored on Microsoft
Activation Servers. The Windows 7 or Windows 8 genuine license you were previously running will be exchanged for a diagnostics key.

Anytime you need to reinstall Windows 10 on that machine, just proceed to reinstall Windows 10. It will automatically reactivate.
You will prompted to enter a product key a couple times through the installation, click I don't have a key and Do this later.

There is no need to know or get a new key, but if you have issues with Digital Licensing or the Activation Troubleshooter, you can utilize an existing Windows 7 or Windows 8/8.1 product key
you already ownto reactivate if necessary. or use the reset function in Windows 10.

Step 1: How
to download official Windows 10 ISO files

Step 2:

• How to: Perform a clean install of Windows 10

 

Installing Windows 10 using Windows 7 key

Nope, you need to install Windows 10 first and make sure the Windows 7 key is transferred to your Windows account after you've installed Windows 10 (not quite sure how that works). I missed the last step and I could not activate Windows 10 after a re-install... Microsoft seem to have done everything they can to make it a PITA. Also, it's technically too late to do this now anyhow, as the upgrade offer has expired. But KMSPico works quite well...

As for getting rid of Windows, delete the Windows folder.