When I'm playing Youtube videos, the PC running PlayOn makes 2 or 3 clicking sounds. Specifically, it's playing C:\WINDOWS\Media\Windows Navigation Start(Loud).wav. I renamed the file and it doesn't play the sound any more. PlayOn shouldn't be making noises on the host PC at all.
Please be sure to send in a support ticket through PlayOn Settings so we can figure out why this is happening on your PC.
PlayOn Administrator