Ten days ago, I upgraded Windows 7 to Windows 8 ("What are you waiting for"-email from Microsoft). Within 6 days, I needed to refresh Windows 8 twice because of some crashes. After the second time "refresh", and reinstalling numerous updates for Win8, I turned the computer off. Next morning, after I successfully got the my Desktop screen, a message popped up saying, that my “Outlook driver had some errors and I needed to restart computer”. After I restarted my computer, Windows went through “Scanning hard drive and repairing” process. Suddenly, I got a message that Windows could not repair the errors and will be automatically restored to a previous state. After about 40 minutes, I got a message that Windows could not be restored to a previous state. I got an option to go Advanced Options. Several times, I've tried and failed to refresh or reset my Windows 8. I even tried to run chkdsk in MS-DOS. It failed with a note, saying something about “could not transfer log ...50”. Sorry, I don't remember the exact words. I tried to repair my Windows 8 by using USB Flash Drive, but got a message saying that my hard-drive is locked. Over-the-phone Microsoft technicians could not help me. I decided to do a “clean-install” of Windows 8 on the same computer that had Win8 installed. I got a message, saying something “Windows cannot be installed on GPT drive, only on MBR”. I needed to reformat my hard drive – to loose everything – and only then, I was able to reinstall Windows 8. Why I could not refresh my Windows 8? Could anyone tell me about that GPT drive?