I type in my correct email and password and the correct user name but it keeps saying "You cannot sign in using another user's sign-in ID (e-mail address)." I can't figure out how to fix this. Anyone know how?
You are using a PS3 user profile that is already signed up for PSN using a different PSN account. Create another PS3 User to use with this PSN account, or use the Restore Default Settings command in the System Settings menu to clear the existing PSN information from the currently logged-in user profile.