The default Dell Bios password is ( Dell ) for Dell bios master password please visit the Dell Bios master password page once you have the right dell Bios master password in hands, type the password and press enter, try also to apply the password from inside BIOS setup. Also, Dell can issue a 'Master Password' to the owner of the equipment. Unfortunately, you aren't the original owner, and I doubt they transferred ownership via THE DELL TRANSFER OWNERSHIP PAGE. Hopefully you can get back with whoever sold it and organize this so you can get in. Might be worth a call to Dell customer service anyway. You might have to prove that ownership was transferred somehow, or maybe you get someone who just gives you the password, if you're lucky. Good luck!