I too had trouble with the remote when I first set these speakers up. I actually wasn't surprised, because I read a review where someone said the speakers worked great, but the remote didn't. Anyway, I did what a previous poster in this discussion said, and went to the Logitech site and downloaded the up-to-date software for the z-5s. The remote is now working great.
I uninstalled the software that was on my computer (which I had installed using the CD that came with the speakers), and then downloaded and installed the software from the Logitech site. I don't plan to keep the CD, as the software on it doesn't seem to be current.
The Z-5s look like pretty nice speakers, the sound is good, and although I don't see myself using the remote all that much, I'm happy to know it works for when I want it.
