If you have created, opened or received your email recently, check the entries in the Cookies (the input string ' sites), there are usually stores information about all input addresses. For this you need to click on the arrow that is located at the right end of the row. If the list of addresses will appear your email address, you just need it to move, clicking on a hyperlink.
If you have not used this address in the row input address sites not, try to contact those whom you sent an email on the email address that you want to remember. Perhaps they have kept your letters in a folder "Inbox" or "Trash", and they just want to dictate your address.
If you forgot your password email, click on the "forgot password", "remember password" or "recover password" in your email agent. This button is usually located under the fields where you need to enter the address and password. There you will need to provide your email address, which will receive a new password or a link to a page where you will be able to choose a new password.