It’s possible the previous owner did not release their AppleID ownership of this device before passing it on. Just conjecture…but I’d hope you would get some kind of message telling you that. This mac is old enough that the last bootcamp drivers Apple put out won’t support it, but if you have the ones that came with the default OS for that model, you should still be able to install Windows…but you would need an installation disk for Windows 7 or maybe 8, which was current at the time. Windows 10 came out in 2015. As for removing Mac OS completely…I don’t know. I don’t think you can just install another OS directly onto a mac without special installers running in Mac OS. Although their be some Linux distros that made special installation disks for macs.
It’s possible the previous owner did not release their AppleID ownership of this device before passing it on. Just conjecture…but I’d hope you would get some kind of message telling you that. This mac is old enough that the last bootcamp drivers Apple put out won’t support it, but if you have the ones that came with the default OS for that model, you should still be able to install Windows…but you would need an installation disk for Windows 7 or maybe 8, which was current at the time. Windows 10 came out in 2015. As for removing Mac OS completely…I don’t know. I don’t think you can just install another OS directly onto a mac without special installers running in Mac OS. Although their be some Linux distros that made special installation disks for macs.