You don't want F8. That's a windows menu for boot options.
When you boot your pc as soon as anything appears on the screen look for the key to hit to enter the recovery partition. Study the lower part of the screen as the option appears very briefly and you need to hit the key immediately. It might take a couple of goes to get it.
As Grumpy has said you want the destructive recovery. Bear in mind that everything WILL be wiped and your pc will be factory condition.