System recovery

Hello,
i own a Toshiba satellite a505-s6965 i want to do a factory recovery on it because i bought it from a friend but there is a lot of junk on it. now i have tried holding in the 0 (zero) key while turning on the laptop but the warning screen never appears like it is said to. i have also tried to press f12 while the system is booting and i was told to look for an hdd recovery option which also doesn't appear i just want to know where i can buy a recovery disk for my laptop or actually find a way to recover my laptop that actually works... any help would be greatly appreciated.