I was trying to activate Windows 8, I got “This product key didn’t work. Please check it and try again”, using a valid key that came with the Windows 8 software. I called Microsoft Customer care to solve this issue and record it for everyone to see. Click here to see what Microsoft did to activate Windows 8
Steps to solve This Key didn’t work. Please check it and try again, or try a different key in Windows 8:
1. Press the Windows Key + R to open a run window and type: “Regedit”
2. Then located this key:
3. Find the one called “MediaBootInstall“.
4. Double click that and change the Value Data from 1 to a 0.
5. Then open the command prompt as an administrator. To do this just move your cursor to the top right corner, select the search, and search for command prompt under settings, right click and run as administrator.
6. In the command prompt window type “slmgr /rearm” and press enter.
7. You will get a restart your computer message. so restart.
8. when your computer restarts press the Windows Key + R to open a run window and type “slui.exe 3” and enter your product key. When finished click activate button.
9. If step 8 didn’t activate your Windows 8 then press the Windows Key + R to open a run box again and type “slui.exe 4”
10. In the following window select the country of region. Click OK.
11. Now follow the steps described on the screen by calling the toll free number.