since I have only MACs, I was not able to easily delete the U3 stuff. I did take it to a friend's PC and although I had to download a newer program (the uninstaller), I was eventually able to delete the U3. There is a bug where the U3 installer, if it sees other slots (even if no device in 'em, such as as a multi-slot card reader), the uninstaller fails.

I had to go thru some hoops on this friend's PC, but I finally got rid of the U3 stuff - and now that stick works OK on my S900.