I bought last year an Asus laptop which was preinstalled with Windows 8 (non-Pro) x64 and had an embedded product key. Even once the harddrive was formatted, the setup read the key embedded in the chip and chose the non-Pro edition automatically so that clean reinstallation could be completed when an en_windows_8_x64_dvd_915440.iso disc was used. Then Windows 8.1 was released and its update followed it. Every time however I try to make clean installation of Windows 8.1 (with Update) using a disc of en_windows_8_1_x64_dvd_2707217.iso or en_windows_8.1_with_update_x64_dvd_4065090.iso, the setup cannot recognize the embedded key nor manual inputs of the key (read with RWEverything) can be accepted (invalid key). I don't want to start with en_windows_8_x64_dvd_915440.iso every time to reach "Windows 8.1 with Update". Help would be appreciated.
read the key of your bios, install 8.1 from scratch using the generic key and later activate with your 8 key > done