Windows 8 Pro Product Key Doesn't work

I keep getting this error: "This product key didn't work. Please check it and try again"

Just bought the Windows 8 Pro upgrade from Windows 7 home premium.  Installed fresh from a USB thumb drive...
Got mine sorted out....i called customer guys can check it out here for your respective countries 

So yea...explain to them the situation, they will provide you with this diagnostic the package, reset your comp...and you should be able to activate your shiny new os...they were quick in resolving my issue...kudos to them...hope this helps =D

Method for those who don't want to phone customer service:

Your key is an update only key... meaning it won't allow a fresh install... unless you do the registry workaround from Windows 7.

You need to open a run box and type: "Regedit"

Then located this key:


And find the one called "MediaBootInstall".

Double click that and change it from a 1 to a 0.

Then open up cmd as an administrator

Type the command "slmgr /rearm"

You will get a restart your computer messge.


Then when your computer restarts you need to open a run box again and type "slui.exe 3" and it will allow you to enter your product key and activate :)

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Question Info

Last updated April 8, 2021 Views 107,164 Applies to: