Microsoft — Upgraded to windows 10 and i lost all my data including operating system is not working it is blank screen and can't go back to windows 8.1

Address:	560093
Website:	www.update.microsoft.com/windowsupdate/v6/vistadefault.aspx?ln=en-US

I will definitely complaint this to Consumer forums and sue a case in court if possible on Microsoft... it is nonsense as I Upgraded to Windows 10 and I lost all my data including windows 10 operating system is not working it is blank screen and can't go back to windows 8.1... After so much long waited near by 20 hours my windows 8.1 upgraded to windows 10 and incidentally it is not working and showing blank screen... when I search in google about this so many customers also facing the same issue and most of them are not able to resolve it. My copy of the windows is genuine and I even lost my windows 8.1 also. And in Microsoft website they simply told this should be fix by windows updated... this is really bull how can any body will update with blank screen (http://www.update.microsoft.com/windowsupdate/v6/vistadefault.aspx?ln=en-US) this is really badddddddddddd from Microsoft...