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When I press the 'Esc' key to stop all sound, there is an annoying beep.
Is there any way to stop this?

This is probably related to a Windows setting. If you are using Windows XP, go to Start / Control Panel / Sounds and Audio Devices. Then click on the Sounds tab. Do you have a 'Sound Scheme' selected? If so, I suggest you change this to 'No Sounds'. If you are not using Windows XP there will be some similar method of turning off this sound.