I was messing with this for 5 hours last night. I figured out that you need a windows 7 sp1 that is up to date on updates or Windows 8.1 that is up to date with ALL updates except .net Frame work updates. You also need to have the update installed for the windows 10 notification and reserve your copy of windows 10. Also the windows 7 and windows 8.1 would have to be activated. Then start the windows 10 setup from a bootable USB flash drive or DVD-R with windows 10 while your on your up to date windows 7 and 8.1.
If you are reverting back to a non up to date windows 7 and 8.1 and ran the Windows 10 installer on it the Windows 10 installer will use a generic key that is blocked from getting your free copy of windows 10.
When you reserve your copy of windows 10 the notification program injects a unique key during windows 10 installation which will automatically activate.
To tell if you botched the upgrade with the generic key is that the last 5 digits of the key would be either H8Q99 for home edition of 10, 3V66T for Pro edition, Windows 10 home single language YTDFH and last Windows 10 enterprise 2YT43. You will find this in the settings of windows 10 under activation option.
Like Brink says. Install your windows 7 sp1 or 8.1 you had. Update the windows 7 and 8.1 with all updates first. The windows 7 and 8.1 will have to be activated too for this to work. Usually not an issue on Prebuilt OEM computers. You do not need the .net frame work updates just everything else. Make sure you got the windows 10 notification update installed. You will know when you got it there will be an Icon near your clock to reserve the upgrade to 10. Make sure you reserve a copy of windows 10 before you begin. Then run the windows 10 setup from an ISO that was copied to a DVD-R or USB stick using rufus 2.2 or some other USB creation tool instead of waiting for the notification tool to download the windows 10 for you. I recommend you use the keep files and settings option so you can return to the previous windows version.
You can get the ISO/DVD image file here.
Windows 10 ISO Download
Last edited by flood404; 04 Aug 2015 at 20:23. Reason: typo
You're most welcome Patrick. I look forward to hearing how it went.
I installed windows 10 pro from the iso file from microsoft. Everything is ok but i wanna personalize my windows. It asked me for activation key. I tried W a lot of keys and nothing... Only 1 worked: NPPR9-FWDCX-D2C8J-H872K-2YT43 and then my Win10 pro became Win10 Enterprise. It says my current key is this but when i click the button ,,activate" i got this error: 0xC004F074: The Key Management Server (KMS) is unavailable" I tried ALL the cmd fixes and things and stuff and i am going to give up. I don't know how to remove this error. Please guys tell me what to do, please. As i read comments above, a man/girl said that he or she also had problems but magically it worked on the next morning and windows got activated. Please tell me all that you know. Thanks!
Hello iTeddy, and welcome to Ten Forums.
Did you do an upgrade install to the free Windows 10 from within an activated Windows 7/8.1?
If not, then that is why your Windows 10 is not activated.