It's all fixed and works. If anybody is wondering how this turned out, here's the begining o
f the results.

index.php

<?php

if (!($f=fopen("sc_serv.conf","r")))
  exit("Unable to open file.");
  while (!feof($f))
  {
    $x=fgets($f, 100);
    list($variable, $data) = explode("=", $x);
    echo "<form method=\"POST\" action=\"update.php\"> ";
    if ($variable == "MaxUser") {
     echo "Max Users: <input type=\"text\" value=\"$data\" name=\"MaxUser\" size=\"3\"> <br /
> ";
    }
    if ($variable == "Password") {
     echo "Password: <input type=\"text\" value=\"$data\" name=\"Password\" size=\"15\"> <br 
/> ";
    }
    // echo "$variable $data<br /> ";
  }
fclose($f);

echo "<p /> <input type=\"SUBMIT\" value=\"Submit\" /></form>";

?> 

update.php

<?

$newconfig = "";

$maxuser=$_POST['maxuser'];
$password=$_POST['password'];

foreach($_POST as $area =>  $value) {
   $newconfig .= $area . "=" . $value . "\n";
}


$fp = fopen('sc_serv.conf', 'w');
fputs($fp, $newconfig);
fclose($fp);


exit();

?> 

Thankyou to everyone who helped. Special thanks to Chris.