You should reset the password via the "forgot password" tool. Then you'll receive the email with the link, which allows to reset the password.
As regards to the PIN-codes, they are not regenerated via that tool. If you do not know the current PIN-code, you should generate a new list of PIN-codes via shell:
http://help.x-cart.com/index.php?title=X-Payments:User_manual#Generating_PIN_codes_for_othe r_users