Think about whether you can contact someone from your contacts for help. Maybe someone of your friends have received your messages and will indicate forgotten the address. There is another option. For example, you register on any website, putting the mailbox as your username. By accessing the website, you can find it.
Use any other way to restore the email addresses. Go to the resource that was your Inbox. Next to the Windows login and password there is a link "Forgot?", "Remember password" and other such labels, depending on the site.
Click on it. You will see the page on restoration of email. If you visited this portal from your PC, in window "Login" most browsers can leave the name of the last entered record. If this does not help, look carefully through the web page to restore access. Usually post resources here post.
By clicking on the link, you will learn how is the process of restoring the mailbox name. Thus, in particular, need to know additional email address that you provided when creating your account. The user selects from the one that he noted at the time of registration, and gives the answer. Then you need to do all the necessary steps to recover the password and login to remember your e-mail.
If none of these options are not suitable, please contact your site administration. Write a letter, stating the reason of your problem. Be polite in words and don't use rude language. You need to be prepared for the fact that administrators will ask questions. After all, you need to prove that you are – this is the user who can't remember your e-mail.