What is the difference when buying windows 7 from upgrade and full?
 

I am using program that comes Office Pro Plus 2010 Activation Key and I am considering getting Windows 7. I have been shopping online and I have found Office Pro 2010 32 Bit and Windows 7 Upgrade. When I think of an upgrade, I think of it as something to improve Office 2010 Generator I already have. Is this the case with Windows 7 Home Basic? Is it an improvement on Windows 7? If so, why hasn't the upgrade been integrated with the Windows 7 software?