Just sorting out an older laptop. Its a Toshiba Satellite that came pre-installed with Windows 7 Home Premium 64Bit OEM. At some point someone reinstalled and used the COA licence. I checked and it had SLIC2.1 but no OEM Cert. installed. I then installed the correct Toshiba Cert. manually using slmgr.vbs then changed the key to the OEM toshiba one for W7 HP. It is then activated fine and working as genuine. I then wanted to upgrade it to Professional, so used the Anytime Upgrade in the System page using the Toshiba OEM SLP Pro key. As per expected it gives you the fail notification page but upon reboot it normally upgrades just fine. It has worked previously with this method. On reboot it remains at Home Premium with no Upgrade. I then deleted the WAU key from the registry and tried another Pro key but again the same result. Is there some Windows Update installed that now blocks this? (note KB971033 or KB2952664 are not installed). Whats the quickest other method to achieve the upgrade without a re-install?