Step 5 - If you do not enter the product key you can still proceed with the installation in which case Windows will ask you which version of Vista you have purchased. Windows Vista Home Basic, Home Premium, Ultimate, Business etc. Select the version you have purchased and click next.
Please note, although you can select any version of Windows and proceed to next stage. It is not good idea to select a different version to the one you have purchased becuase you will not be able to activate Windows at a later stage. Windows Vista can detect which version you have purchased once you enter your product key.