Hi! Sorry to hear that you are having trouble with this situation. Is this Windows user account connected to a Microsoft account? If it is, you will need to use the Microsoft account password, not the Gmail password.
Are you able to sign in with this account at Outlook.com? Also, could you please clarify what you mean when you say this email does not exist on other devices?
Finally, have you already tried using the password recovery option during the sign-in process?