
I can understand what situation you are in now. As I don't have a Windows 7 computer to test now, I can only give you some suggestions to try.
I guess you're using a Microsoft account to log in Edge Chromium. When you log in once, the account has been remembered by the computer and you can use it to sign in Microsoft apps. The only way is to delete the account in computer account settings. You can refer to this thread and this article to try the methods in them to see if you can delete the account.
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Regards,
Yu Zhou