How to unlock a Hard Drive and Refresh PC

Solution 1:

Erasing the system is not what you want!

To make the system boot again, you need to fix the EFI boot stuff. It's related to messages like

The windows boot configuration data file does not contain a valid OS entry
The drive where Windows is installed is locked. Unlock the drive and try again.

Follow these steps - see this blog

1. Use a Windows DVD (or USB Stick) to open a repair command prompt.

   Troubleshoot -> Advanced Options -> Command Prompt

2. Execute these steps - do not enter the comments. But adjust the numbers and the Windows path to match your configuration.

   // start the disk partition tool
   diskpart    
   // if you have more disks find the correct disk and use its number
   sel disk 0
   // if you have more disks find the correct disk and use its number
   list vol
   // the drive where EFI is on is usually the first FAT32 volume - here 2
   sel vol 2
   // make that volume accessible
   assign letter=z:
   // leave the partition tool
   exit  
   // navigate to the EFI stuff
   z: 
   cd z:\EFI\Microsoft\Boot\
   // fix the boot record
   bootrec /fixboot
   // restore the boot menu - adjust the path to match your windows location
   bcdboot c:\Windows /s z:
   

This is what worked for me.