...

 if($username && $userid){
      echo "You are already logged in";
    }
    else {
    $form= "<form action='./login.php' method='post'>
    <table>
      <tr>
        <td>Username:</td>
        <td><input type='text' placeholder='Username' name='user'</td>
      </tr>
      <tr>
        <td>Password:</td>
        <td><input type='password' placeholder='Password' name='password'</td>
      </tr>
      <tr>
        <td></td>
        <td><input type='submit' name='loginbtn' value='Login'</td>
      </tr>
      <td><a href='register.php'>Register</a></td>
      </tr>
    </table>
    </form>";

    if($_POST['loginbtn']) {
      $user = $_POST['user'];
      $password = $_POST['password'];

        if($user) {
          if($password) {
            require("connect.php");//brings in the connect.php

            $password = md5(md5("sd3fdDS^&S".$password."&12fd(*s&DSD"));

            $query = mysql_query("SELECT * FROM users WHERE username='$user'");
            $numrows = mysql_num_rows($query);
            if($numrows == 1){
              $row = mysql_fetch_assoc($query);
              $dbid = $row['id'];
              $dbuser = $row['username'];
              $dbpass = $row['password'];
              $dbemail = $row['email'];
              $dbActive = $row['Active'];

              if($password == $dbpass){
                if($dbActive == 1){
                  //set session info
                  $userid = $_SESSION['userid'];
                  $username = $_SESSION['username'];

                  echo "You have been logged in!Click <a href='loggedin.php'>here</a> to view the member page";

                }
                else
                  echo "Incorrect password. $form";
              }
              else
                echo "You must activate you account to login. $form";
            }
            else
              echo "User not found. $form";

            mysql_close();//closes connection to databade
          }

          else
            echo "You must enter your Password. $form";
        }

        else
          echo "You must enter your username. $form";
    }
    else
      echo $form;