switch($_GET[action]){
    case "check": //checks for blank fields

//======I THINK MY 1st PROBLEM STARTS HERE============
$scname=filter_string($_GET['scname']);
$email=filter_email($_GET['email']);
$psw=filter_string($_GET['password']);
$psw2=filter_string($_GET['passw2']);
$queryScname=check_input($_GET['scname']);

if(!filter_input(INPUT_GET, "$email", FILTER_VALIDATE_EMAIL)){
     echo "<font color='#D5C513'><strong>E-mail is not valid.</font></strong><br />";
}
else {
    return $value;
}
//=========================  
    
    if(strlen($scname)>7 && strlen($scname)<26 && strlen($email)>7 && strlen($psw)>7
                          && strlen($psw)<26 && strlen($psw2)>0 && $psw == $psw2){

    // Connect to server and select database.
$con = mysql_connect("$host", "$username", "$password")or die("cannot connect server" . mysql_error());
mysql_select_db("$db_name")or die("cannot select DB" . mysql_error());
$sql=("SELECT COUNT(scname) FROM $tbl WHERE scname='$scname'");
$result=mysql_query($sql);
$rows=mysql_fetch_array($result);    
    
    //screen name check    
            if($rows[0] == 0) {
           $sql2=mysql_query("INSERT INTO temps (scname, password, datetime, email, code)
                        VALUES('$scname', '$psw', '$date', '$email', '$_POST[code]')");
        mysql_close($con);    
        
        //send email
        $body="Welcome and thank you for becoming a part of iEroticXpressions.com.  
                Your screen name has been successfully created.  
                After you have confirmed your account you may begin posting.
                Click on the link and use the activation key provided to complete your account registration. \n \n";
        $body.="Screen Name: $scname\n";
        $body.="Activation Key: $_POST[code]\n";
        $body.="Password: $psw\n";
        $from="admin@iEroticXpressions.com";
        $header="From: $from";
        mail("$email","IEX Mail",$body,$header);
        print "Only one more step to complete registration.  Please check your email for further instructions.";
        break;
        }    
        else
        print "<font color='#D5C513'><strong>Submission Incomplete!</strong><hr>
                <strong>$scname</strong> is already in use.
                Chose another screen name and try again.
                You may try including the underscore, period, or dash in your choice of screen name.</font><hr>";
    }        
            
    else{
        print "<font color='#D5C513'><strong>Submission error!</strong> Please try again.<hr>
            1) Check to make sure you've filled out all of the fields.<br/>
            2) Make sure your passwords match and that you've used only<br />    
            alphanumeric characters (A-Z and/or 0-9).<br/>
            3) In all fields you may also use the underscore, period, or dash.<hr></font><br />";
        include("includes/newaccounts.inc.php");
        break;
    }    
    default:
    include("includes/newaccounts.inc.php");
    break;
      
}      
//==
function filter_string($value){
    var_dump(filter_var($value, FILTER_SANITIZE_STRING, FILTER_FLAG_STRIP_LOW));
    return $value;
}
  
//===== AND 2nd ERROR HERE =============
function check_input($value){
// Stripslashes
if (get_magic_quotes_gpc())  {
  $value = stripslashes($value);
  }
// Quote if not a number
if (!is_numeric($value))  {
  $value = "'" . mysql_real_escape_string($value) . "'";
  }
return $value;
}
//======================

function filter_email($value){
    var_dump(filter_var($value, FILTER_SANITIZE_EMAIL));
    }

// Connect to server and select database.
$con = mysql_connect("$host", "$username", "$password")or die("cannot connect server" . mysql_error());
mysql_select_db("$db_name")or die("cannot select DB" . mysql_error());

switch($_GET[action]){
    case "check": //checks fields
    
//==================
$scname=filter_string($_POST['scname']);
$psw=filter_string($_POST['password']);
$psw2=filter_string($_POST['passw2']);
$queryScname=check_input($_POST['scname']);

$email=filter_email($_POST['email']);

function filter_email($value){
    var_dump(filter_var($value, FILTER_SANITIZE_EMAIL));
    
    if(!filter_var($value, FILTER_VALIDATE_EMAIL)){
     echo "<font color='#D5C513'><strong>E-mail is not valid.</font></strong>";
     }
     else {
        return $value;
     }
    }
//==================
    if(strlen($scname)>7 && strlen($scname)<26 && strlen($email)>7 && strlen($psw)>7 && strlen($psw)<26 && strlen($psw2)>0 && $psw == $psw2){

<?php
$var="<b>Peter Griffin<b>";
var_dump(filter_var($var, FILTER_SANITIZE_STRING));
?>

string(13) "Peter Griffin"

    //removes HTML coding & special characters
function filter_string($value){
    var_dump(trim(filter_var($value, FILTER_SANITIZE_STRING, FILTER_FLAG_STRIP_LOW)));
    return $value;
}

function filter_email($value){
    var_dump(filter_var($value, FILTER_SANITIZE_EMAIL));
    
    if(!filter_var($value, FILTER_VALIDATE_EMAIL)){
     echo "<font color='#D5C513'><strong>E-mail is not valid.</font></strong>";
     }
     else {
        return $value;
     }
    }

function check_input($value){
// Stripslashes
if (get_magic_quotes_gpc())  {
  $value = stripslashes($value);
  }
// Quote if not a number
if (!is_numeric($value))  {
  $value = "'" . mysql_real_escape_string($value) . "'";
  }
return $value;
}