I have windows 10 pro x64 free upgrade after full booting all dialogue boxes does not open,as freezed,tried to boot from windows DVD to repair installation but no success,then tried to reinstall I received message "The drive where windows is installed is locked,unlock the drive and try again"I do not use Bitlocker,Windows 10 was running fine for months,I can boot PC from Windows 7 installed on dual boot and it runs fine,I cannot find reason for Windows 10 not running and drive locked,any help is very much appreciated.