in reply to
How to use Threads
Your operating system is already multithreaded. Your task would be easier suited to using that than the in-language thread support:
opendir(DIR, $directoryLocation);
my @files = grep(/\.html$/,readdir(DIR));
closedir(DIR);
my @cmd = qw( start perl c:/html2wordxml.pl );
foreach my $file ( @files ) {
system( @cmd => $file );
}
In other words, make a program that knows how to reformat a single file, and then call that program repeatedly without waiting for the last call to finish.