Click "Restore" on the left hand pane, then select "Completely restore system to factory defaults"
2. From Booting your laptop:
Start up your laptop, and as soon as your see the Acer logo, press ALT & F10 - you may need to continually tap the F10 key. This will access the eRecovery program. Some models will also allow you to press F8 when you see the logo, then click "Repair your Computer" then there will be a option to start the eRecovery from there.
Just remember to backup everything beforehand, otherwise you'll loose all your personal files.