If its newer model model it has a recovery partition on it but I have no idea which OS
Home Premium is personal desktops and
Windows 7 Ultimate is for cooperate computers
what the previous owners did what is called a "Anytime Update" he would have to download the Ultimate edition and buy a anytime Update key for that specific version
OT: If you work at a Pawn shop would you sell that as is minus delete all the previous owner stuff or re install windows 7 home edition or Windows 7 Ultimate
If I was a consumer, I said I wanted that drive wipe for security reasons you would do that in your store policy I would buy the computer not at retail + a OS for it. In the total cost of that computer.