How do you sign out your Microsoft account everywhere? If you are on the device that you would like to keep, you are halfway there to get your issue solved.
Personal Microsoft Account
Your personal account will be one that was created by Microsoft (such as msn.com, live.com, hotmail.com) and can be done from https://account.microsoft.com where you can unlink from the devices that show access to your account.
School or Work Microsoft Account
Your school or your work account will be the one that has the school or company domain name in the email address and can be done from https://mysignins.microsoft.com/ where you can unlink from the apps and devices that show access to your account.
