If you are unable to get into Windows to start the
recovery then you start the process when you first
switch on the PC.
As soon as you turn on your PC, tap the F11 key on the
keyboard until you get the "Windows is loading files..."
When Recovery Manager has loaded click advanced options
Choose system recovery
If you wish to try and backup any data then choose
backup your files first and follow the on screen
To run the recovery without backing up your data choose
to recover without back up
The recovery will launch and restore your system back to
it's factory default state