Can't do a factory reset cause I don't know admin pw

Yes my ex just gave me her old computer and she literally forgot her admin password and doesn't want to try and remember cause she has a new updated one but I have no way of performing a factory reset because she literally denied her guest account from performing what to do she refuses to sign a documents proving that it is my laptop so I can have a professional fix it but no she says it is a old computer and u can have fun fixing it I need to know if there is a way to get around admin password or if there is a place in Reno Nevada that can help me out