I have figured out my OEM Windows Product Key (this is for a Windows 8 Core/64 bit OS).I have changed my boot priority to put the CD/DVD drive first and any flashdrive 2nd.I disabled 3 things in the BIOS: IIRC, they were secure boot, quick boot, and something about 'optimized' startup.I couldn't even boot from a disc or flashdrive without those 3 things disabled, regardless of my boot priority.I would like to perform a clean install of Windows 8.1 on this computer. I have recently purchased a new Lenovo C540 that has Windows 8 already installed on it (please note I have posted in Lenovo forums, awaiting solution there as well).