If I decide to format my drive and use the same product key for my OS I used prior the format, will it work or would I need to buy another OS to get the key?
You can use the same product key on the same system without issue. I think, after the third activation (again on the same system), you may need to call in to Microsoft in order to get it activated.
You can use the same product key on the same system without issue. I think, after the third activation (again on the same system), you may need to call in to Microsoft in order to get it activated.