In order for Visual Studio to run, it not only needs its binaries and other files, but also certain registry entries. The registry is part of the OS. So in addition to the Visual Studio binaries and files that are installed in your portable drive, you will need to provide some sort of script like .REG files to import its settings into the registry so that Visual Studio can be executed.
«_Superman_» I love work. It gives me something to do between weekends.