As you know, no COA sticker. I downloaded MICROSOFT.WINDOWS.8.1.RTM.X64.ENGLISH.DVD but it wants a product key when I boot from it. I thought it was supposed to take the product key that is embedded in the BIOS? UEFI is on on BIOS. Am I using the wrong version of Windows 8 DVD? Toshiba C855-S5350 I believe it came with Win 8 (regular) x64 I have Googled for hours, this shouldn't be this damn hard. I just want to reinstall the OS.