Hi, I have a genuine product key of Windows 7 but don't have its copy (DVD/ISO image). In this case, is it possible and lawful to install Windows 8 from a genuine copy of "Windows 8 Upgrade"? I don't want to buy the full version since it's a bit more expensive. Thanks, Culip P.S. So here's the whole story: I purchased my laptop "Panasonic Japan Let'snote J10" in Japan. The laptop doesn't have an optical drive but it has "Windows 7 Japanese" and a "Windows recovery program (partition)" stored in its hard drive. And neither Windows 7 nor the recovery program works--but oddly enough, scandisk doesn't detect any error in the hard drive. Linux in the same hard drive has been working perfectly, which implies that the hardware is healthy.