After 48 hours of troubleshooting the Windows 8.1 installation that knocked out USB drivers and made computer unusable, I gave up and decided to "Refresh" the OS from DVD. It was supposed to reinstall OS Win. 8 without affecting personal files. When I attempted, it stated, "Your drive is locked. Please, unlock the drive and try again". What does it mean- my drive is locked? It appears that Win 8.1 did something weird, making it impossible to return back to 8.0. Did anybody ever heard about locked drive containing OS? I am wondering if it will say the same when I try to clean install Win 8.0. Thank you.