The bitcoin core program wallet should tell you the password you are typing, typed or copy and pasted. That way cases like this would never exist.
That would create much bigger problems: anybody could read it from your screen!
The common solution against typing errors is to enter the password twice, but just to be sure, I always test if I can unlock my wallet anyway.
maybe the password could be a wallet address cause I remember i sent many coins to mt-gox and after that I encrypted the wallet.
Your best odds are to reproduce everything you've ever copy/pasted. You're in luck if it's a used Bitcoin address, as they're all public information and can be extracted from the blockchain.
Brute force is the only thing that would work here, given bitcoin price now and what it could reach and quantum computers, maybe now is hard but in few years or decades would be possible
With 44 random characters you don't stand a chance, unless a vulnerability in the encryption will be found in the future.
Not sure, just throwing something here: maybe you had an invisible character at the end of password?
Like a new line: \n
You could be on to something here: Notepad and Wordpad handle those in a different way. You could even try installing the same Windows version, just in case (even though it's a long shot, it's a lot more likely than brute forcing it).