Yes, it is possible to install the Studio 12 upgrade in this scenario.
Note #1: This FAQ applies to both Windows XP and Windows Vista. The screenshots were taken using Windows XP, but the Windows Vista screenshots will look very similar.
Note #2: This procedure will work even if the previously owned version of Studio will not install in Windows Vista (Studio 9 for example).
Here is how to install:
1. Insert the Studio 12 upgrade disc and you will see this image. Hit the Install S12 entry.
2. Chose the proper language when it asks like in this image
3. The installation will prompt you to hold down the shift key and insert the previous version disc.
4. You may be prompted to enter the older version S/N like in this screen
5. Once this is done, the installation will now prompt you to re-insert the Studio 12 upgrade disc.
6. After the Studio 12 upgrade disc is inserted, the installation will prompt you to enter the serial number of the new Studio version.
7. The Studio 12 installation will begin.