Hi, I previously purchased a Lenovo Yoga laptop which was preinstalled with Windows 8 (non-Pro) x64 and had an embedded product key. I then updated to Windows 8.1 where a new product key was issued and afterwards work then paid for me to upgrade to the Pro version, where I was then issued with a new prouct key. Obviously, it's the initial product key that's in my bios. I now wish to reformat the laptop and install a clean version of Windows 8.1 Pro x64. Could someone please advise which of the following should I use: a) 9600.16384.130821-1623_x64fre_Client_SingleLanguage_EN-US-IRM_CSLA_DV5 b) en_windows_8.1_core_single_language_CSLAx64_ga_dvd c) en_windows_8.1_with_update_x64_dvd_4065090 In addition, I have added a 2nd SSD drive to this laptop. Could I install Windows 7 Pro on one of the drives and then Windows 8.1 on the other drive and still maintain UEFI within the bios, as I understand Windows 7 may not boot if I have UEFI switched on in the bios? Any assistance would be appreciate thanks.