I am sorry to hear you are having this issue. Have you tried removing the batteries from the remote to see if the inputs still change? This will help determine if the issue is with the remote or the unit itself.
The Blu Ray player switches source on its own quite frequently. Usually from HDMI1 or HDMI2 to D.in or FM. It has happened for a while so I updated to the latest firmware and now it happens more often. Any help?