How to get rid of the gong sound when enter is hit in textbox?

Subclass from TextBox, override ProcessDialogKey and do the following:

protected override bool ProcessDialogKey(Keys keyData)
{
	if(keyData == Keys.Return)
	{
		return true;
	}
	else if(keyData == Keys.Escape)
	{
		return true;
	}
	else
		return base.ProcessDialogKey(keyData);
}

The idea is to prevent the base class from processing certain keys.