Code Testinput.php Error ตรง if(isset(($_GET["login"] !== "null")) กับ if(isset(($_GET["show"] !== "null")) ครับ

<form method="post" action="TestInput.php" enctype="multipart/form-data">
	สมัคร ข้อมูลส่วนตัว
	<table>
	<tr>
		<td>รหัส</td>
		<td><input type="text" name="txtId"></td>
	</tr>
	<tr>
		<td>ชื่อ</td>
		<td><input type="text" name="txtName"></td>
	</tr>
	<tr>
		<td>Password</td>
		<td><input type="text" name="txtPassword"></td>
	</tr>

	</table>
	<input type="hidden" name="MAX_FILE_SIZE" value="102400" />
	<input type="file" name="fupload" /><br/>
	<input type="submit" name="register" value="Add">
	<input type="submit" name="login" value="login">
	<input type="submit" name="show" value="show">
</form>

<?php
	if(isset($_POST["Add"]))
	
		print $_POST["txt"];
		mysql_connect("localhost","root","123456");
        mysql_select_db("tum");

      $txtid = $_POST['txtId'];
      $txtname = $_POST['txtName'];
	  $txtpassword = $_POST['txtPassword'];

      $query = "INSERT INTO student(ID , Name , Password) values('$txtid','$txtname','$txtpassword')";
      $result = mysql_query($query);

      // Display an appropriate message
     if ($result) 
         print "<p>Product successfully inserted!</p>";
      else 
         print "<p>There was a problem inserting the name!</p>";
      mysql_close();

        if(isset(($_GET["login"] !== "null"))
	{
	$objConnect = mysql_connect("localhost","root","123456") or die("Error Connect to Database");
	$objDB = mysql_select_db("tum");
	// Search By Name or Email
	$strSQL = "SELECT * FROM customer WHERE (Name LIKE '%".$_GET["txtKeyword"]."%' or Email LIKE '%".$_GET["txtKeyword"]."%' )";
	$objQuery = mysql_query($strSQL) or die ("Error Query [".$strSQL."]");
	?>
	<table width="600" border="1">
	  <tr>
		<th width="91"> <div align="center">CustomerID </div></th>
		<th width="98"> <div align="center">Name </div></th>
		<th width="198"> <div align="center">Email </div></th>
		<th width="97"> <div align="center">CountryCode </div></th>
		<th width="59"> <div align="center">Budget </div></th>
		<th width="71"> <div align="center">Used </div></th>
	  </tr>
	<?php
	while($objResult = mysql_fetch_array($objQuery))
	{
	?>
	  <tr>
		<td><div align="center"><?php echo $objResult["CustomerID"];?></div></td>
		<td><?php echo $objResult["Name"];?></td>
		<td><?php echo $objResult["Email"];?></td>
		<td><div align="center"><?php echo $objResult["CountryCode"];?></div></td>
		<td align="right"><?php echo $objResult["Budget"];?></td>
		<td align="right"><?php echo $objResult["Used"];?></td>
	  </tr>
	<?php
	}
	?>
	</table>
	<?php
	mysql_close($objConnect);
        }

if(isset(($_GET["show"] !== "null"))	 
$objConnect = mysql_connect("localhost","root","root") or die("Error Connect to Database");
$objDB = mysql_select_db("mydatabase");
$strSQL = "SELECT * FROM customer";
$objQuery = mysql_query($strSQL) or die ("Error Query [".$strSQL."]");
?>
<table width="600" border="1">
  <tr>
    <th width="91"> <div align="center">CustomerID </div></th>
    <th width="98"> <div align="center">Name </div></th>
    <th width="198"> <div align="center">Email </div></th>
    <th width="97"> <div align="center">CountryCode </div></th>
    <th width="59"> <div align="center">Budget </div></th>
    <th width="71"> <div align="center">Used </div></th>
  </tr>
<?php
while($objResult = mysql_fetch_array($objQuery))
{
?>
  <tr>
    <td><div align="center"><?php echo $objResult["CustomerID"];?></div></td>
    <td><?php echo $objResult["Name"];?></td>
    <td><?php echo $objResult["Email"];?></td>
    <td><div align="center"><?php echo $objResult["CountryCode"];?></div></td>
    <td align="right"><?php echo $objResult["Budget"];?></td>
    <td align="right"><?php echo $objResult["Used"];?></td>
  </tr>
<?php
}
?>
</table>
<?php
mysql_close($objConnect);
?>