2010 Macbook re-installing iOS

[Pskov]

Hello, I was hoping someone could help me out with this;

I'm new to Apple, this is the first Apple device I have ever used and Im trying to find out if its possible to install the os from bootup like you would on a pc so say Ive inserted a mac os cd and boot up the laptop is it possible to install the os straight from boot up without logging in?

Basically i got the notebook from a friend of mine he doesnt remember his password so the only way i could use the notebook is by re installing ios. I havent actually tried anything yet as i dont have the charger but before i go and buy one im just trying to find out if theres anyway i can use the notebook without being able to login.