The problem is
Windows could not start because the following file (\WINDOWS\SYSTEM32\CONFIG\SYSTEM) is missing or corrupt:
Windows failed to start. A recent hardware or software change might be the cause. To fix problem:
1. insert your windows installation disc and restart your computer.
2. choose your language settings, and click next
3. click "repair your computer"
If yo do not have this disc, contact your administrator system administrator or computer manufacture for assistance.
info : windows failed to load because the system registry file is missing or corrupt
In our case your windows is Windows 7
This problem is exactly the file “\Windows\system32\config\system” may be missing or corrupted and the windows is already have a backup for this file all you need is to copy the backup file to the the current one and restart like the following
With the Windows 7 CD or usb Key boot the system.
Open a command prompt in the recovery console. (Shift + F10)
go to file location (may be windows appear in D not C because usually there is 100 MB may be invisible for booting)
ren SYSTEM SYSTEM.BACKUP
copy regback\SYSTEM SYSTEM
Reboot the system.