I have a computer with an AMD Sempron 3200+, running Windows XP Home ED. I am trying to figure out which version of PHP5, Apache, and MySQL will work on this system.

Hello Dear
There is no way to find MySql version
My code provided you only sqlite version
and phpinfo provide you whole information
about php

<?php
  $agent = getenv("http_user_agent");
  $result = "you are using $agent";
  echo $result;

// prints e.g. 'Current PHP version:XXX'
echo '<br>Current PHP version: ' . phpversion();
//print sqlite version only
echo "<br>sqlversion".sqlite_libversion();
//Print whole information about php
phpinfo();
?>

Regards
Shekhar Srivastava