use feature ":5.14";
use warnings FATAL => qw(all);
use strict;
use Data::Dump qw(dump pp);

my @l = split /\n/, << 'END'; 
Ubuntu,Warty,No
Ubuntu,Hoary,No
Ubuntu,Breezy,Yes
Ubuntu,Breazy,Yes
Fedora,Yarrow,Yes
Fedora,Stentz,No
Fedora,Yarrow,Yes
Fedora,Yarrow,Yes
Windows,XP PRO,Yes
Windows,XP PRO,Yes
Windows,XP Home,No
Windows,XP PRO,Yes
END

my $h;
for(@l)
 {my @w = split /,/;
  $h->{$w[0]}{$w[1]}{$w[2]}++;
 }

pp($h);

for     my $o(sort keys %$h)
 {for   my $r(sort keys %{$h->{$o}})
   {my %yn = %{$h->{$o}{$r}};
    my ($yes, $no) = ($yn{Yes}//0, $yn{No}//0);
    say "$o\t$r\t$yes\t$no";
   }
 }