winmx should work on a memory stick, winmx itself doesn't mind what os it's run under, & the "vista" dll will also work under older versions, to avoid it complaining at startup, setting the incoming (and possibly shared) folders to ones on the memory stick would also be a good idea if you try it. There is, however a possible issue with the patch not loading should such an install be run under win 9x, which relates to a registry setting, and it's worth noting that the life (read/write cycles) of such storage is not limitless, they eventually "wear out" which is why it's not a good plan to say install windows to them..
