I know this should be very simple. BUT I just could not get it work, and I
did not find any documentation on how to close an excel app from MSDN.

I created the app in vb6 as,
Set xlApp = CreateObject("Excel.Application")
Set xlWb = xlApp.Workbooks.Add
Set xlWs = xlWb.Worksheets("Sheet1")
and after populated the sheet,
xlWb.Saveas ("C:\northwind\mynwtbl.xls")
' xlWb.Close
With above line the only the workbook closed, but not excel itself.
' xlApp.Windows("C:\northwind\mynwtbl.xls").Close
With above line I got "subscript out of range" error.
'Set xlApp = Nothing
No working either.

Thanks!