Dim xlApp
Dim xlBook
Dim xlSheet
Dim FileName
Dim iRow
Dim iCol

FileName=...
Set xlApp = CreateObject("Excel.Application")
Set xlBook = xlApp.Workbooks.Open(FileName)
Set xlSheet = xlBook.Worksheets("Sheet1")
...
xlSheet.Cells(iRow, iCol)=...
...

xlApp.DisplayAlerts = False
xlBook.Close True, FileName
xlApp.Quit
Set xlSheet = Nothing
Set xlBook = Nothing
Set xlApp = Nothing