When you try to install Windows Vista, you cannot select the Upgrade option that is located in the Install Windows dialog box. Additionally, you receive the following error message in the dialog box:

Upgrade has been disabled

- Your upgrade partition has multiple operating systems

When you try to install Windows Vista, you cannot select the Upgrade option. Also, receive the following error message in the Install Windows dialog box:

Upgrade has been disabled

- Windows cannot determine if another operating system exists on your computer. Try repairing the boot configuration, and then begin the installation again.