Need help! If someone gives away their laptops to you, ......

Hi, my name is IAPD3000. First timer

Let just say that someone is giving away their old laptop computers for free and they did not erase or delete their user accounts. What should I do?

I just got two Dell laptops as a yard sale or they giving it away. He told me that I need a charger cord for both of them.

One of them is Dell Inspiron 1010 and it works, but he did not erase his account. I don't know this person and I don't want to ask him to solve it. Is there another way to fix this?