If the operating system will not boot and no other troubleshooting can be performed, a recovery of the (C:) drive can be performed by starting the computer and pressing the F10 key.
NOTE: If an Edit Boot Options window is displayed, press the ENTER key to continue.
The Restore Complete System option will delete all partitions and any data saved on those partitions and restores the (C:) drive to its original, factory-installed condition. This option allows changing the size of the (C:) drive.