itunes struggling to work in windows 10 asking for old passwords

Problem 1: I recently switched from mac to PC and downloaded iTunes. I transferred all my music to iTunes, which now shows THREE COPIES of every song.

Problem 2: Whenever I try to play certain older iTunes purchased songs it asks for the old Apple I.D. and password to authorize this computer to play the song. I don't know the old password anymore (9-15 years old), and the new I.D. and password will supposedly allow my computer authorization (I get the message that 3 out of 5 computers have authorization), but I still can't play the songs - I just get the old Apple I.D. and password prompt window again. In iTunes I have "authorized this computer" in settings. When I try to guess my old password, I then get "this apple I.D. has been blocked for security reasons".

Thanks,

Rick