use Win32::OLE;

        # use existing instance if Excel is already running
my $excel = Win32::OLE->GetActiveObject('Excel.Application') || Win32::OLE->new('Excel.Application', 'Quit');
my $workbook = $excel->Workbooks->Open("c:\\your_file.xls");
my $worksheet = $workbook->Worksheets(1);
for my $row(0..$maxRow) {
   for my $col(0..$maxCol) {
      my $cell = $workbook->{Cells}[$row][$col];
      $cell->{Value} = '#Failure' unless($cell->{Value});
   }
}
# save and exit
$workbook->Close();