Safe Mode Password Problem

I received a laptop from a relative that is no longer with us. It will not let me install software on it since I do not know the admin login or password. I googled it and it told me to boot in safe mode. I did the “msconfig” thing and I get the screen for the log in and password….BUT….I need to know the admin log-in and password to get in. Even my normal log-in and password will not work. I am stuck in a perpetual log-in screen. Does anyone know how I can log back into my computer? I would prefer to be able to reset the admin login/password, but anything will do. Thanks