I have a Toshiba 43u6863DB smart Tv which is just over a year old and had very little use. The tv has an optical cable connected for audio output to a home cinema sound system and the tv internal speakers were set to zero volume level. Recently whilst watching the tv and without having touched the remote control, a vertical sound level icon the full screen height appeared on the right hand side of the screen. I am unable to delete this icon, I first tried the ‘exit’ and ‘back’ buttons and then all the remaining buttons on the remote without success. In addition the sound, now coming from the internal speakers, moves independently between the extreme high and low volume positions, alternately cycling between the highest and lowest levels. If I try to change the volume level with the remote the tv automatically resets the level back to the previous highest or lowest level. I have tried to alter the tv system and audio settings using the remote to change the tv menu internal settings but I cannot turn off the internal speakers or set their level back to zero. It almost seems as if a virus has taken over the sound level controls for the internal speakers and is resisting any attempt to reset the internal speakers hack to a zero level but after looking elsewhere on line I have read that it is not possible for a smart tv to be affected by a virus. I would appreciate any suggestions as to possible causes and remedies for the audio problems I am having with the TV.