jQuery dialog for help popup
I would suggest loading the external file and initializing the dialog prior to the event...kind of like:

$(document).ready(function(){
    // make the dialog
    $("#dialog-confirm").load("/help/nameSearch.htm").dialog({
           autoOpen: false,
           resizable: false,
           height: screen.height - 300,
           position: {
               my: "left top",
               at: "left top",
               of: "#Table1"
           },
           width: '790px',
           height: 'auto',
           modal: true,
           buttons: {
               "Okay": function () {
                   $(this).dialog("close");
               }
           },
           hide: { effect: "drop", direction: "up" },
           show: { effect: "drop", direction: "down" }
       });
    }).keypress(function (e) {
       if (e.keycode == $.ui.keyCode.ENTER) {
           $(this).dialog("close");
       }
    });


    $("#Help").click(function () {
        $("#dialog-confirm").dialog( "open" );
    });

});


That way, any delay caused by the loading of the file/creation of the dialog is handled on page load instead of on button click.

Note the addition of the autoOpen:false option. That keeps it from opening on init.