Turning off the sound after hitting "Enter" for fill-in-the-blank (case 22424)

[chrimabro]

Hello. I've muted MediaLab sounds in the "Preferences" folder to prevent the clicking noise that accompanies each trial, but there is still a ding sound when participants hit the "Enter" key for fill-in-the-blank items. I'd like to turn this off, because I'm having participants enter many fill-in-the-blank items so it quickly gets annoying.

Is there a way to turn it off, given that "Mute MediaLab sounds" doesn't work for that particular sound?

Other ideas:
(1) Can I remove the text that says "hit ENTER to continue," so then they won't know they can hit ENTER and they'll press the "Continue" key instead (which is silent)?
(2) Can I delete the sound from a system folder?

Thanks!