If you have a full version Windows, not OEM, or a PC manufacturer bound, like Dell or HP, you are entitled to install it in any computer. The only limitation is, unless you have several licenses, you may only install it in one computer. Multiple licenses allow you to install it in x computers.
The license is not computer bound, it is program bound. If you have a computer that came with Vista, it does not and will not restrict your right to install a legitimate Windows 7. Or Windows 8, or Windows 9... or anything. The copyrights are immaterial, they have nothing to do with a specific computer, except with OEM and manufacturer bound, but are strictly directed towards
the use of a program. In fact, you never own a Windows, you only have the license to use it.
As for upgrading from Vista to Windows 7: yes, you need to install it. It should go as an update... no problems. --- Go figure? I do recommend full versions. It's the full pack, period.
Hope there was something here?
Cheerio.