My email address "******@mezon.lt" no more exists.

To remove the old, non‑working ******@mezon.lt address from the Microsoft account and use a working address instead, the email addresses on the Microsoft account must be managed from the account’s alias settings.

Follow these steps:

1. Go to the “how you sign in” page for the Microsoft account: Edit account info.
2. Sign in with the Microsoft account that still has ******@mezon.lt attached.
3. Under Your info / Account username / Aliases, do the following:
   • If a working email (for example one of the ******@gmail.com addresses) is not yet listed, select Add email and add it as an alias.
   • After adding it, select Make primary next to the working email address so it becomes the primary alias.
4. Once a working address is the primary alias, select Remove next to the old ******@mezon.lt address to delete it from the account.

Important notes from Microsoft’s rules about aliases:

• Email addresses and phone numbers on the account are called aliases and all share the same data, subscriptions, and settings.
• An alias can be removed at any time from the alias list using Remove next to that address.
• If the removed address is from a non‑Microsoft domain (like @mezon.lt), it usually becomes available to be added as an alias on another Microsoft account, but it will no longer be tied to this one.

After this cleanup, sign in to Windows 10 on the laptop using the Microsoft account whose primary alias is now the working Gmail address. That will allow the laptop to be properly registered and associated with the correct Microsoft account.

If sign‑in or verification is blocked because the old address cannot receive codes, on the verification screen choose I don't have any of these, then add a phone number and receive the verification code by text or call.

References:

• Change the email address or phone number for your Microsoft account
• How to add an email address or phone number to your Microsoft account
• Add or remove an email alias in Outlook.com