When and if the installation is completed and you can successfully boot to Vista and Windows 8, then you can install the Windows 8 device drivers and test your access to the keyboard, mouse or touchpad, proper display resolution, USB ports, DVD drive, camera and if everything works then you can connect to the Internet (LAN cable or install the Wireless device driver) to activate Windows.
Finally boot to Windows Vista and create another Image Backup (Disk and Partition, selecting all partitions) now that Windows 8 is installed and activated.
How Windows Vista boots after installing Windows 8: Set Windows Explorer to show hidden files and folders. You should now see all the folders and files located in the Windows Vista partition. There are three key folders and files in Vista (C:\Boot and C:\bootmgr). C:\Boot hold the Boot Configuration Data needed to boot to either Vista or Windows 8.
The graphical boot menu displays two choices “Windows 8”, which is the default version your PC will boot to if you take no action to select “Microsoft Windows Vista” within 30 seconds.
That’s it, you’re done. Well almost done.
If you have a dual boot computer with more than one disk drive you may have noticed that after booting to Windows 8 and then booting to Vista that chkdsk runs before Vista starts. If you are experiencing this problem then read then read this article (Windows 8 - chkdsk always runs on a Dual Boot computer) when you’re ready to make a small change to the way Windows 8 shuts down.