for facebook videos

Cool guide found on wikihow
http://www.wikihow.com/Download-Facebook-Videos-Free

there you go
http://www.downvids.net/

Windows 8 factory reset notebook model Acer V3-571G

On the Login Screen hold shift and move click on shutdown icon. Select 'restart'.
After reboot will be prompted a menu, now you may navigate : troubleshoot > Advanced option >  Reset PC

Please note, doing reset will lose all data.