In these circumstances, I think we can answer in part. You asked if there was a way to format the drive and of course, there is.
Buy a Windows 10 licence key from Microsoft then download the ISO and burn it to a CD if you really want a disk or better still, combine it on to a USB thumb drive using a utility named Rufus to make that stick bootable.
The password will have done its job because the data were protected until they were formatted out of existence.
That said, the machine is of an age which might restrict it from running an overblown modern version of Windows. Maybe a free flavour of Linux would be a better option.