Being as this is a Linux Mint forum perhaps you should have posted your query to a Windows Forum.
In short it is generally an accepted fact that Windows Vista is a horribly bloated and slow OS and Windows 7 is a significant improvement, so if you must buy something to contribute further to Microsoft's $$billions then go with Win 7.
Both the same aren't they, Windows, Life without Walls as the slogan goes. If no walls what's holding the Windows up? and why would you need Windows in the first place. Don't work does it. Who writes this ****.