My email address disapeared from my screen.

Now which email account was it ????

Important information can sometimes be sent to an old email address that you no longer use.
For instance, if you registered a domain name, a website hosting account, a PayPal, or eBay account with an old email address but forgot to update your account when you switched email providers, then messages sent by those sites will be overlooked.
Finding old email accounts is not that difficult, especially because email users tend to use the same user name, or variations of it, for all email accounts.
If you know, or have an idea of what the old user name was, then retrieving, or changing the password is simple, but each email server uses a different user name or password retrieval method.

Call your internet provider and tell them you have forgotten your email account.
Give them your name and account number, found on your monthly statement.
In some cases the Internet provider will want to email this information to you.
Be sure they send the information to the alternate email address which you can access.
You don't want them to send messages to the email address you can't currently access.
The internet provider will ask you the security question you selected when signing up for the account.
If you can't remember what you selected, then the customer service representative may ask for a user name, your address, or the telephone number under which you registered the account.
Reset the password with the customer service representative over the phone.
The representative will help you change the user name if needed and reset the password so you can access the account again.
Yahoo Email
Go to the Yahoo mail page which asks you for your Yahoo ID.
Click on "I can't access my account."
Make the appropriate selection from the choices.
If you choose "I can't remember my user ID" then Yahoo will have you answer the "secret questions" they asked when you signed up.
These questions will be something like: "What was your first car?" or "Who was your third grade teacher?" If you answer coincides with the answer you gave when you signed up for the account.
Yahoo will give you your user ID.
After recovering your user ID, click on "I can't access my account" again and select "I can't remember my password," then click next and you will be taken to a change password screen, where you can change your password.
Start using your old Yahoo email account.
MSN Hotmail Email
Go to the Hotmail, or the MSN ID page, where it asks for your user name and password
Enter your user ID.
Unfortunately, MSN requires you to remember the user ID.
Click on "I have forgotten password"
Choose whether you want your password mailed to you or changed.
Unless you have registered a secondary email, if you choose email then the password will be sent to the account you can't access.
If you want to change password then you will be asked the security questions you specified when you registered the account.
Questions are something similar to, "Mothers birth place?" You may also be asked for your zip code, or address.
Enter a new password.
Enter anew password when the MSN ID page loads again and access your old email account.
Gmail Email
Access the Gmail ID page and click on "I can't access my account."
Choose the appropriate selection from the page that loads.
Options include, "I have forgotten my password" and "I have forgotten my user name."
If you select "I forgot user name," then click on "retrieve user name page," which you will see further down on the page.
Enter the alternate e-mail with which you registered the account.
The user name will be sent to that email.
Select "I have forgotten my password" If you know your user name then choose and click on "retrieve password" page.
Enter your user name on the page that comes up and then answer the confidential question that is asked.
Send password reset instructions to an alternate email and access your old Gmail email account.