Important note

If you’re using this code for anything requiring real security (i.e. not just a student project) MD5 is not an appropriate hashing algorithm. Read through the OWASP advice to learn how to do this properly.

Answering your question

You have:

$psd= md5($_POST['psw']);
$confirm_psd= $_POST['confirm_psw'];
if ($psd == $confirm_psd)
{
    ...

which looks like you’re comparing the plain text value of confirm_psd with the MD5 hashed value of psw, which obviously won’t match.

I’d suggest you either do the comparison before hashing the psw field, like:

$confirm_psd= $_POST['confirm_psw'];
if ($_POST['psw'] == $confirm_psd)
{
    $psd= md5($_POST['psw']);
    ...

Or also hash the confirm_psw value before the comparison like this:

$psd= md5($_POST['psw']);
$confirm_psd= md5($_POST['confirm_psw']);
if ($psd == $confirm_psd)
{
    ...

and then your comparison should work as you expect.