Sony has revealed that in conjunction with their restoration of services, they have been working on a PS3 system software update that requires all PSN users to change their password. The update (v3.61) is mandatory and is available now. Your password can only be changed on your own PS3 (or a PS3 on which your PSN account was activated), as an added layer of security. If you have never downloaded any content using your account on the system, an email will be sent to the registered sign-in ID (email address) associated with your account when you first attempt to sign-in to PSN. This e-mail will contain a link that will enable you to change your password. In this email, click on the link and follow the instructions. Once you have changed your password you can sign-in to your account using your new password.