As I said, I have personal experience with this - the product we were trying to register had sold with that name in the past, but the PTO rejected our applicati

As I said, I have personal experience with this - the product we were trying to register had sold with that name in the past, but the PTO rejected our application. We never got to the point where a challenge could be made. We resubmitted a new name that had many more qualifiers added, and that one was accepted. It's just as well, because Microsoft came out with something shortly after that had the same name. Definitely not someone you want to do battle with.