need help wiping everything off my laptop

[Strawberry12]

I have a Toshiba laptop that I have for long time now, I have passwords on it that I forgot what they were. I tried rebooting it by holding down the "zero" 0 button and the power button down then it will beep for a long time but it will just go back to starting normally.
so please someone help me

 

[RealBeast]

While we cannot give password assistance, you can wipe the drive completely by downloading and running the free version of DBAN from a USB stick.