Hello and welcome to JA.
When upgrading to Windows 10, it may have caused the EUDORA package to corrupt, and that is why it is not working.
Additionally, when looking into this issue I read this:
it is Mozilla's understanding that Qualcomm is no longer developing Eudora OSE and its community support forum no longer exists. Furthermore, the last released version is based on an old version of Thunderbird which is no longer supported, has many bugs and performance problems, and known security issues. ~~ ~~ Users might like to try Thunderbird as an alternative email program. The user interface and features are not the same, but Thunderbird has an active support community, and its features and UI can be improved with addons, which in some cases add Eudora-like functionality.
I would recommend you do as it states, and get Thunderbird, and ditch Eudora.
For the password ***** you will need to ask the network admin for that domain MAIL.BRESNAN.NET for the password ***** be recovered or replaced. Unfortunatley, Bresnan has become CHARTER, and there is a process that you need to follow in order to keep using the mail features.
Go here, and continue to recover your password, and you will most likely have to make changes within your email client to accommodate the changes within Bresnan becoming Charter.
Go here for help switching from Bresnan to Charter.
If you need support from charter, which I think you will, here is their support page.
JustAnwer is NOT able to help you get your password ***** YOU MUST CONTACT charter