In this post, I showed you how to make an “universal install DVD” for Windows 7. In a nutshell, by deleting one file from a Windows 7 install DVD, you can have the edited disc prompt you for which version of the OS you want to install. You can’t use this tweak to get free upgrades – the version you can use is tied to your product key – but the tweak comes in handy for IT support staff who might need to install many different versions of Windows.
I have found a similar tweak for Windows Vista, and it works in a similar way:
1) Using a disc imaging utility like PowerISO, make an image of the Windows Vista installation DVD.
2) Extract a file called SETUP.CFG from the “Inf” folder inside the “Sources” folder in the root of the drive image.
3) Open the file with a text editor like Notepad and scroll to the bottom of the file. There you will see something that looks like this:
4) Delete these two lines and save the edited file, then overwrite the existing configuration file in the ISO image.
5) Burn the edited ISO to disc.
When you run setup using the edited disc, do not enter a product key when prompted; on the next screen you will be asked which version of Vista you want to install. You can then enter the product key after setup completes.
The only “gotcha” to this is that I’m fairly certain that you need a Windows Vista Ultimate disc to create the ISO, as Vista Ultimate is the only one that contains all the installation files for every version of the OS.