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.
The first window will look like the following:
Enter your email address and click next.
This Window will appear:
Since you do not know your password, click on "Try a different question"
In the process you may be asked for either to answer your secret question or your alternate email or phone number.
You Have not Registered Alternate Recovery Options
Unfortunately if, when you created the account, you have not registered a secret question which you remember, an alternate recovery email address or phone number to which you have access to receive a reset code, you cannot prove that you are the account's legitimate owner. Hence account recovery is absolutely impossible and there is no way around it.
Your Mobile Phone Number Has Been Changed
If you have changed your mobile phone number you can recover your account only if you remember your password. Head for this link to recover your account, a reset code will be sent to your alternate recovery address or phone. You will be asked for your password.
Your Gmail Account has been Hacked
If your account has been hacked or compromised, Gmail offers a step-by-step recovery process that begins with a questionnaire. Click on the previous hyperlink to access the questionnaire.
After you have entered your email address, Gmail will ask you for the last password you have used and then will ask you where you wish to have the reset code sent to you.
A reset code will immediately be dispatched to you, on the next window you will be asked to enter the six digit reset code and you will gain access to your account. Check you sms or email for the code.
If you do not have a mobile number to receive a reset code, click on "Try a different question", you should then be able to enter an alternate email address to get the code.
Gmail Account Unaccessed for 9 Months
If you have not accessed your Gmail account for approximately 9 months, 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.