Windows 7 - can i install windows 7 again after upgrade Clean Installation

Hello, Im new to this, and my question is sort of the same, i have a family pack of Home Premium and i need to do a clean install of windows 7 because of problems but i do not want to use another product key of the three, i have already used two and one of them is the computer i want to do a clean install on, will it use another product chance?

Thanks

You can reinstall retail Windows 7 with the same valid key as many times as you want. If your hardware changes, you might need to make a robocall during activation to update it.

When you boot the DVD it will scan the HD to see any OS, which is enough to pass a flag allowing use of Upgrade version key.

If you need to wipe the HD first to clean possible infection, then you will need to run an Upgrade install from the newly installed Windows 7 desktop to get it to accept Upgrade version Product Key.