Lost Access to Xbox 360 Email

You do not remember the email for the account?

Or

You know the email but do not remember the password for the account?

If you do not remember the email for the account but know the gamertag you can contact xbox support by going to support.xbox.com/contact-us and request either a callback or chat with a support agent. Once you are in contact with them if you give them you
gamertag and they can verify ownership of the account they can give you the email that is associated with the account. At which time you can go to account.microsoft.com/acsr and try to recover/reset the password for the account.

If you know the email for the account you can try and recover the account/password by going to account.microsoft.com/acsr

If you do know the old email (even if it isn't existing anymore), you can try to log into that Microsoft Account. If it's a third party email (like Gmail, Yahoo or your old work or school email), the email is just a username string that looks like your old
email. It is actually a separate account, so even if your old email doesn't exist, you should be able to sign in.

HOWEVER: Microsoft also checks some security questions and might send a confirmation code to that old non-existent email. So if you didn't have any backup like a secondary email or a phone number to text you the code, you might not be able to sign in to
that account.

If you were able to sign into that old account, make sure that you add recovery emails and phone numbers at

https://account.live.com/Proofs/Manage

As for combining your two accounts: You can't combine two Microsoft Accounts. If your new account has NOT made purchases or doesn't have important data, you could delete your new Microsoft Account, sign into the old Microsoft Account, and create a new Alias
using the deleted new Microsoft Account information. Make your new Microsoft Account address the Primary Sign in Alias, and you should be golden.

However, if you have made purchases on the new account, you can't take them with you. So you'll have to decide which is more important for you.

Hopefully this link will help you out https://support.microsoft.com/en-us/help/17875/microsoft-account-reset-or-recover-password

If you loose access to the original email the GamerTag is associated with, it can become impossible to retrieve access to the DLC purchased under it. So, for instance, if you have a local Broadband email account when you get the map-pack or whatever and
a couple of years later, under a different ISP, you go to transfer the DLC to a new Xbox 360 and you no longer have access to that original email, XBL will not be able to verify your ownership, and it will not be transferable. I know several people who have
lost items purchased from Live because of this.

Hey mate, do you still have an Xbox 360 console where you can sign-in to the gamertag? I'm guessing no if you've lost the email, but the following link has steps to do so if you still have access to the account on the 360:

support.xbox.com/.../switch-gamertag-to-different-microsoft-account

If you've lost all access to the account, I'd suggest getting in contact Xbox phone support and seeing if they can help you change the email by proving you own the account through other personal details:
support.xbox.com/contact-us