my $Excel =  Win32::OLE->GetActiveObject('Excel.Application');
unless ($Excel) {
    $Excel = Win32::OLE->new('Excel.Application');
}
my $xls = $Excel->Workbooks->Open(...);
my $sheet = $xls->Worksheets(1);

##</code><code>##

 my $lastrow = $sheet->UsedRange->Find(
        {   What            => "*",
            SearchDirection => xlPrevious,
            SearchOrder     => xlByRows
        }
    )->{Row};