You have quicktime and when you watch it it has no sound what do you do?

If QuickTime is playing video without sound, first check the volume settings on both QuickTime and your computer to ensure they are turned up and not muted. Next, verify that the correct audio output device is selected in your system settings. You might also try restarting QuickTime or your computer, or reinstalling QuickTime if the issue persists. Lastly, check if other media players have sound to rule out hardware issues.