If there are no spaces in the path name and the file's permissions are set to allow execute access you can do this:

    system("start $filename");
[download]

But the better way to do it is to install Win32::API via the PPM command (or CPAN); then you can do this:

use Win32 qw(SW_SHOWNORMAL);
use Win32::API;
use strict;

my $FILE_OR_URL = ... whatever ...;
my $shellexec = Win32::API->new('shell32', 'ShellExecute', 
  'NPPPPI', 'N') or die "cannot import ShellExecute: $!\n";

my $result = $shellexec->Call(0, "open", $FILE_OR_URL, 
       "", ".", SW_SHOWNORMAL);
if ($result < 33) {
  print STDERR Win32::FormatMessage($result), "\n";
  exit(1);
}
[download]