To start we need toPlease first confirm what you have:

1) Master private key as you claim, it starts with "xprv..."
2) A .wallet file.
3) Individual private keys usually beginning with 5, K or L.

If you have "xprv.." I would assume it is a BIP32 wallet. In that case you have two options.

1. Download Electrum and import the key: https://electrum.org/.
2. Save/download this website https://iancoleman.io/bip39/ and then open it in your browser locally (you need to open the index.html file probably). You can input the master private key there (BIP32 Root Key) and derive your addresses. You may need hardened derivation ticked, check addresses of both in case you are unable to locate anything.

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In any case if you are genuine about this, do not share any of this information with anyone. If there are any funds on that wallet they can steal them using your key and you won't be able to do anything about it. Are you absolutely sure you had funds on this wallet?

To start we need to first confirm what you have:

1) Master private key as you claim, it starts with "xprv..."
2) A .wallet file.
3) Individual private keys usually beginning with 5, K or L.

If you have "xprv.." I would assume it is a BIP32 wallet. In that case you have two options.

1. Download Electrum and import the key.
2. Save/download this website https://iancoleman.io/bip39/ and then open it in your browser locally (you need to open the index.html file probably). You can input the master private key there (BIP32 Root Key) and derive your addresses.