This has been driving me crazy and giving me a nasty headache for the last few hours. I don't know how to stop it from changing and playing the ding, but I have worked out how to turn the volume of the ding down to zero. Go into options and towards the bottom there is a setting for Interface Volume. Set that to zero and no more dinging. Obviously there'll be no noises for working through the menus and whatnot either while that volume is at zero.