use strict;
use Win32::OLE qw(in with);
use Win32::OLE::Const 'Microsoft PowerPoint';
$Win32::OLE::Warn = 2; # Throw Errors, I'll catch them

my $PptApp  = Win32::OLE->GetActiveObject('PowerPoint.Application')|| 
+Win32::OLE->new('PowerPoint.Application', 'Quit'); 

$PptApp->{Visible} = 1;
my $Presentation = $PptApp->Presentations->Open({FileName=>'test.ppt'});