Thank you for the reply!
bitcoin.dat file => maybe, it could *potentially* be your wallet, a .dat extension could also mean it's a wallet that has been generated using bitcoin core.
If it is so, could you please tell how I can use it or where I can read about it? It isn't available for choosing in the attempt to open existing wallet. And all the search keeps pointing me to the wallet.dat file (damn these too smart search engines)
password > only usefull *if* it's the pasword from your bitcoin.dat. IF it's a private key, it *could* be the private key of one of your addresses... It would be even better if it were a master private key. Electrum's master private key starts with xprv. Could you tell us what's the first letter and how many characters this password has?
It is 34 characters long and starts with digits '14'.