I have a dell laptop computer which I bought at a estate sale... it was working fine until one day it said I need to enter a bypass authentication code which I do not have... I really need to use this computer and can not afford another one... I contacted dell regarding this and since the warranty is over they are reluctant to help me without having to pay for a new warranty... can anyone help

Exactly where are you being prompted for this authentication code ?

I have used a number of Dells and never come across this before.

Are you talking about the operating system? Some come with a short term trial and then you have to pay for actual software.