It will help if you provide detail steps you took to restore you account.

Thanks for helping me with this! When I log into Thunderbird, I first have to enter a primary password which I never had to do before. Once this is entered, a box pops up saying "Set Up Your Existing Email". I enter my name, email address and password, then my configurations are verified. I believe it might be an old password but I don't see anywhere to reset the password. How do I reset a password and get in to my existing account?

You aren't sharing everything. A new profile does not have a password. Did you have a saved profile? Did you restore it? If not, it seems that a part of a prior profile is there. Did you do a fresh install of Thunderbird? By crash, did you have to restore Windows too? You mention two passwords, one to start Thunderbird and one for your account. From your wording, it seems you knew the primary password, but do not know your email account password. True? Please clarify and we'll go from there. Thanks.