New
#11
As others have said, fresh install Windows 7 rather than using the hard drive with the old Windows on it. It will make the build easier when all is said and done.
Since you have the upgrade version of Win 7, you will need to follow one of the methods on this page Clean Install with a Upgrade Windows 7 Version to install from the upgrade media. You can also use a fourth method which is to double install described here.
Have fun with the new build.