Not working PHP and Mysql Update code...

Hey guys,
I set up a form and wanted to have the info inside the form update what is in the database, but its not working, I know its because of the PHP code, here it is:

<?php

$id=$_GET['Username'];
$Username=$_POST['Username'];
$Flashdev=$_POST['Flashdev'];
$Password=$_POST['Password'];
$EmailAddress=$_POST['EmailAddress'];
$Paypal=$_POST['Paypal'];
$Alertpay=$_POST['Alertpay'];
$Videos=$_POST['Videos'];
$Money=$_POST['Money'];
$ClanLeader=$_POST['ClanLeader'];
$ClanName=$_POST['ClanName'];
$InClan=$_POST['InClan'];
$ClanIMG=$_POST['ClanIMG'];
$Admin=$_POST['Admin'];


$con = mysql_connect("localhost", "*hidden*", "*password hidden*");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db("*hidden*", $con);

$query="UPDATE users SET Username='".mysql_real_escape_string($Username)."', Flashdev ='".mysql_real_escape_string($Flashdev)."', Password ='".mysql_real_escape_string($Pwassword)."', EmailAddress ='".mysql_real_escape_string($EmailAddress)."', Paypal ='".mysql_real_escape_string($Paypal)."', Alerypay ='".mysql_real_escape_string($Alertpay)."', Videos ='".mysql_real_escape_string($Videos)."', Money ='".mysql_real_escape_string($Money)."', ClanLeader ='".mysql_real_escape_string($ClanLeader)."', ClanName ='".mysql_real_escape_string($ClanName)."', ClanIMG ='".mysql_real_escape_string($ClanIMG)."', Admin ='".mysql_real_escape_string($Admin)."' WHERE Username = ".$id;
mysql_query($query);
echo "Record Updated";
mysql_close();
?> 

Code (markup):

Please help me! I have been working endless hours on figuring out why it isn't working :/