I don't remember the email address I use to login to fortnight on my PlayStation 4 how do I find out what it is?

you would need to remember what your old email address is and then go to the login page and look for a small link which says "forgot password" and follow the instructions, you need to reset the password for your old email and get back in, if you get back in ok but no longer require that email address you can setup an email forwarder or redirect in the settings menu and tell it to send a copy of all emails to your new email address, this will help prevent any similar probs in future.

By the way, it would help to know what your trying to login to.

To safeguard user privacy, the Facebook login process requires the input of an email address, username or mobile number as well as a password.
While you may opt for the "Remember Me" and "Remember My Password" features on your personal device, there may be times when you need to manually log in to your account.
If you're not able to locate your account from the login page, there are several steps you can take to recover it.Invalid or Expired Email Address
1. If you no longer have access to the email address that is linked to your Facebook account because it is invalid or expired, locate your account by logging in with an alternative.
If you registered a username, enter it in the "Email" field on the login page.
Enter your password and select the "Login" button. If unsuccessful, type your mobile phone number in the "Email" field on the login page.
Enter your password and select the "Login" button.
This will work if you've registered for Facebook texts.
If unsuccessful, type an alternate email address in the "Email" field on the login page.
Enter your password and select the "Login" button.
If you are still unable to identify your account, complete and submit the "I Cannot Identify My Account" report, which you'll find at facebook.com/help.
Click "Browse Help Center Topics" in the left column. Click the "Login & Password" option under "Managing Your Account."
Click on "I Can't Remember Which Email Address I Use To Log In To Facebook" and click the link in option 5.
Click the "I Can't Identify My Account" link in the lower-left corner of the resulting page to access the report.
2 . After you've logged in, click the "Account Settings" option that appears in the "Account" drop-down menu in the upper-right corner of any page.
3. Click the "Change" link next to the "Email" option of the "Settings" tab.
View your current email settings and edit as desired to manage email addresses that can be used for login.
Invalid Password
4. Visit facebook.com/recover.php in your browser.
5. Enter your email address or mobile phone number in the "Email or Phone" field that appears at the top of the page or enter your Facebook username in the space provided.
If you don't know the email address, mobile phone number or username that is associated with your account, type your name and the name of a friend in the spaces provided at the bottom of the page and click "Search."
6. Type the words that appear in the resulting security box to authenticate your request and click "Submit."
7. If the information that appears on the resulting page matches your account, click the "Reset Password" option to access your account.

To safeguard user privacy, the Facebook login process requires the input of an email address, username or mobile number as well as a password.
While you may opt for the "Remember Me" and "Remember My Password" features on your personal device, there may be times when you need to manually log in to your account.
If you're not able to locate your account from the login page, there are several steps you can take to recover it.Invalid or Expired Email Address
1. If you no longer have access to the email address that is linked to your Facebook account because it is invalid or expired, locate your account by logging in with an alternative.
If you registered a username, enter it in the "Email" field on the login page.
Enter your password and select the "Login" button. If unsuccessful, type your mobile phone number in the "Email" field on the login page.
Enter your password and select the "Login" button.
This will work if you've registered for Facebook texts.
If unsuccessful, type an alternate email address in the "Email" field on the login page.
Enter your password and select the "Login" button.
If you are still unable to identify your account, complete and submit the "I Cannot Identify My Account" report, which you'll find at facebook.com/help.
Click "Browse Help Center Topics" in the left column. Click the "Login & Password" option under "Managing Your Account."
Click on "I Can't Remember Which Email Address I Use To Log In To Facebook" and click the link in option 5.
Click the "I Can't Identify My Account" link in the lower-left corner of the resulting page to access the report.
2 . After you've logged in, click the "Account Settings" option that appears in the "Account" drop-down menu in the upper-right corner of any page.
3. Click the "Change" link next to the "Email" option of the "Settings" tab.
View your current email settings and edit as desired to manage email addresses that can be used for login.
Invalid Password
4. Visit facebook.com/recover.php in your browser.
5. Enter your email address or mobile phone number in the "Email or Phone" field that appears at the top of the page or enter your Facebook username in the space provided.
If you don't know the email address, mobile phone number or username that is associated with your account, type your name and the name of a friend in the spaces provided at the bottom of the page and click "Search."
6. Type the words that appear in the resulting security box to authenticate your request and click "Submit."
7. If the information that appears on the resulting page matches your account, click the "Reset Password" option to access your account.
https://www.facebook.com/recover.php
Identify your Account
http://www.facebook.com/help/?faq=18012
How can I make sure I don't lose access to my account

To safeguard user privacy, the Facebook login process requires the input of an email address, username or mobile number as well as a password.
While you may opt for the "Remember Me" and "Remember My Password" features on your personal device, there may be times when you need to manually log in to your account.
If you're not able to locate your account from the login page, there are several steps you can take to recover it.Invalid or Expired Email Address
1. If you no longer have access to the email address that is linked to your Facebook account because it is invalid or expired, locate your account by logging in with an alternative.
If you registered a username, enter it in the "Email" field on the login page.
Enter your password and select the "Login" button. If unsuccessful, type your mobile phone number in the "Email" field on the login page.
Enter your password and select the "Login" button.
This will work if you've registered for Facebook texts.
If unsuccessful, type an alternate email address in the "Email" field on the login page.
Enter your password and select the "Login" button.
If you are still unable to identify your account, complete and submit the "I Cannot Identify My Account" report, which you'll find at facebook.com/help.
Click "Browse Help Center Topics" in the left column. Click the "Login & Password" option under "Managing Your Account."
Click on "I Can't Remember Which Email Address I Use To Log In To Facebook" and click the link in option 5.
Click the "I Can't Identify My Account" link in the lower-left corner of the resulting page to access the report.
2 . After you've logged in, click the "Account Settings" option that appears in the "Account" drop-down menu in the upper-right corner of any page.
3. Click the "Change" link next to the "Email" option of the "Settings" tab.
View your current email settings and edit as desired to manage email addresses that can be used for login.
Invalid Password
4. Visit facebook.com/recover.php in your browser.
5. Enter your email address or mobile phone number in the "Email or Phone" field that appears at the top of the page or enter your Facebook username in the space provided.
If you don't know the email address, mobile phone number or username that is associated with your account, type your name and the name of a friend in the spaces provided at the bottom of the page and click "Search."
6. Type the words that appear in the resulting security box to authenticate your request and click "Submit."
7. If the information that appears on the resulting page matches your account, click the "Reset Password" option to access your account.

To safeguard user privacy, the Facebook login process requires the input of an email address, username or mobile number as well as a password.
While you may opt for the "Remember Me" and "Remember My Password" features on your personal device, there may be times when you need to manually log in to your account.
If you're not able to locate your account from the login page, there are several steps you can take to recover it.Invalid or Expired Email Address
1. If you no longer have access to the email address that is linked to your Facebook account because it is invalid or expired, locate your account by logging in with an alternative.
If you registered a username, enter it in the "Email" field on the login page.
Enter your password and select the "Login" button. If unsuccessful, type your mobile phone number in the "Email" field on the login page.
Enter your password and select the "Login" button.
This will work if you've registered for Facebook texts.
If unsuccessful, type an alternate email address in the "Email" field on the login page.
Enter your password and select the "Login" button.
If you are still unable to identify your account, complete and submit the "I Cannot Identify My Account" report, which you'll find at facebook.com/help.
Click "Browse Help Center Topics" in the left column. Click the "Login & Password" option under "Managing Your Account."
Click on "I Can't Remember Which Email Address I Use To Log In To Facebook" and click the link in option 5.
Click the "I Can't Identify My Account" link in the lower-left corner of the resulting page to access the report.
2 . After you've logged in, click the "Account Settings" option that appears in the "Account" drop-down menu in the upper-right corner of any page.
3. Click the "Change" link next to the "Email" option of the "Settings" tab.
View your current email settings and edit as desired to manage email addresses that can be used for login.
Invalid Password
4. Visit facebook.com/recover.php in your browser.
5. Enter your email address or mobile phone number in the "Email or Phone" field that appears at the top of the page or enter your Facebook username in the space provided.
If you don't know the email address, mobile phone number or username that is associated with your account, type your name and the name of a friend in the spaces provided at the bottom of the page and click "Search."
6. Type the words that appear in the resulting security box to authenticate your request and click "Submit."
7. If the information that appears on the resulting page matches your account, click the "Reset Password" option to access your account.
https://www.facebook.com/recover.php
Identify your Account
http://www.facebook.com/help/?faq=18012
How can I make sure I don't lose access to my account

Use your Facebook login, contact MySpace, or create another account.

my first question would be, do you have a facebook? because then you have an email, maybe one different from your gmail, and maybe your in your address book.
Or maybe you can ask an aquaintance whom you've emailed with what your adress is?
if you can find your gmail address, you'll be okay, because gmail has an option under the normal login for forgotten usernames and/ or passwords, but they require the email address I'm sorry:( if you don't use you old one, perhaps creating a new one might be the most beneficial?

1) Enter the facebook login page.

2) Click on "Help" at the bottom right of the page.

3) Click on "Login and Password".
4) Click on "I can't remember wich email address I use to login to Facebook".

5) Follow the instructions.

The only way to do this would be to completely restore the PS3 system so that when it next turns on it asks for your information.

Hope this helps

this is your plastation network online information you signed up for when you first went online to play video games, shop at there store ect.

If you forgot this information go to this link, and you can get password reset being you forgot it if you know what email you used.

https://store.playstation.com/login.gvm