Yes, Atomic should work , i have designed it for that.
i made some CD for friends where Atomic is installed and can run directly.
the only constraint is to keep all folder Relative to Atomic.
the best thing being to install all under the Atomic folder (including emulators and roms)
Then in Atomic when you reference a folder you give his relative path not the full path.
Then your entire Atomic Folder will be transportable where you want and will run.
Atomic has been designed to work with the need of adding or installing something else on Windows XP . It uses only standard component.
Note that if you use "attract video" instead of snap... you could need to have to install the video codec.
Same thing for the intro video. For a real portable settings, i suggest you disable it. (even if the codec is provided with Atomic, you have to install it).
If you need help feel free to ask on my forums.
http://spaceinvaders.7.forumer.com/viewforum.php?f=13&sid=faafa86d7843e54a9d3af30c3f70137b