See also : Make Windows XP Genuine | Windows Genuine Advantage (WGA) Notifications
Windows 8 license keys are different from Windows 7 license keys and it might not work for Windows 8 because there is a lots of changes in the algorithm producing license keys, In older days people were used to create Product license keys by guessing random number but nowadays the producing the keys are quite changed.
how to get Genuine Windows 8 product License keys for free :
Well Microsoft will never give you a Genuine Windows 8 product License keys for free, but if you are looking for free copy of windows 8 there might be some hope.Microsoft Windows 8 is expected to be released on the next year,full edition of Windows 8 will not be provided to any one but there is some hope to get Beta edition of Windows 8.Windows 8 beta version will require the product license keys or not has not also been cleared yet.
If You are taking Windows 8 product License keys from any illegal websites or source, You are denying the rule and copyright law of Microsoft.