If you've forgotten the password to your Gmail account, you may recover your account by going to Gmail's web password recovery site and filling in their form.
My Gmail Account has been Hacked
If your account has been hacked, Gmail offers a step-by-step recovery process that begins with a short questionnaire. Follow the steps outlined in the forum to recover your password and safeguard your account against future breaches.
Forgot Gmail Password and Security Questions
Unfortunately, if you have forgotten both your Gmail password and security questions, account recovery is basically impossible.
Gmail Account Unaccessed for 30 Days
If you have not accessed your Gmail account for over 30 days, it may have been deleted from the Gmail server. Inactive accounts and the data stored within are usually impossible to recover. Unfortunately, if this is the case for you, you must create a new account, taking care to note your password and security questions in a safe place.
This document entitled « Gmail Account Recovery » from CCM (ccm.net) is made available under the Creative Commons license. You can copy, modify copies of this page, under the conditions stipulated by the license, as this note appears clearly.