foreach my $software (keys %bad_stuff) {
    if($subkey =~ $bad_stuff{$software}) {
        next if($installed_software{$machine.$software}++);
        print "Machine $machine could have $software installed\n";
    }
}

##</code><code>##

foreach my $subkey ($user_key->SubKeyNames,$software_key->SubKeyNames) {
     if ( exists $bad_stuff{$subkey} ) {
	print "Machine $computer could have $subkey installed\n";
     }
						 
}