how to add all occupied cells in one row

[lrneilson]

Hi all
could someone explain how I make this work
all I need to do is add occupied cells from A1 to the first empty column

thanks

<script type="text/javascript">
<!--
    alert("NC = Cells(1, Columns.Count).End(xlToLeft).Column + 1
how do I do this: =Sum(A1:NC)");
//-->
</script>