If you are having trouble activating Windows 8 it may be because you were never presented with an option to enter the key however these commands will help you change the Windows 8 Key. After installing Windows 8 Enterprise on my Dell 6500 I had an issue activating it which I found out happened to a few other people as well. What happens is I was never prompted to enter my key and the option to change the key was missing. After following this procedure Windows 8 Enterprise was successfully activated.
Right click the left hand corner of your Windows 8 screen and Click Command Prompt (Admin)
At the command prompt, type: slmgr.vbs -ipk <then type your product key>
Hit Enter on your keyboard, then type: slmgr.vbs -ato
That’s it and note that this should work on any edition of Windows 8 that you use.
The SLUI 3 Command is another option
If you bring up the run command or a command prompt you can type in “SLUI 3″ and hit enter.
You should see the Windows Activation box come up and ask you for a key. Put your Key in and Press Activate
After you hit Activate you will see the activating Windows Box come up
Thanks Ftcreator for the tip!!