Mine does the same thing, but freezes at 59%. Only displays error code after I restart it and it restores the previous version. Tried so many things and nothing works. Microsoft tech support had me remove my wireless card, and that didn't work either.
Thanks for the suggestions. I haven't knowingly installed any encryption software...is there someway to tell? As for the graphics driver, my first try I was on some default WDDM driver. For my second try, I updated to the latest driver that was specifically for my graphics card from AMD. No BIOS...
I've tried everything I know to do. Maybe you have some ideas.
I have an HP p6720f that came with Windows 7 installed. I upgraded to 8 with no issues around December of last year.
I downloaded 8.1 from the Windows app store without problem. I tried the first install without changing anything...