Try searching for fd1701308201130201010420 in the wallet using a hex editor. (Or perhaps some smaller portion like 0201010420). The next 32 bytes after that string would be your private key, assuming super old, unencrypted wallets.

Edit: Oh. Also, show how you're searching for these strings in the hex editor. (With a screenshot, and not with your wallet.dat open just so nothing private is revealed.) Most allow for searching for text and hexadecimal. Maybe you're searching for hexadecimal as text or something.