Thanks for the replies, I appreciate all help with this - Loganota - the funds were DEFINITELY showing in the wallet originally, so the move from coinexchange.io to the wallet was fine. I used cryptoid to check the original transaction once the balance "disappeared" from the wallet. (To see if somebody had maybe hacked my wallet & removed the eqt from it.)
I'm at a loss with this, I've tried everything - ohforf said to move the .dat backup manually into the %appdata% folder of the wallet manually, rather than execute this within the wallet, (this was a good while ago) - tried this, no joy. The problem I now have is, because coinexchange.io is gone, I'm unable to search cryptoid again to confirm that the balance hasn't been moved out of the wallet. (I tried seaarching with the current "receiving" address for the wallet, this doesn't show anything.
Out of curiosity, I checked one of the blocks from within the "debug" section of the wallet:
https://chainz.cryptoid.info/eqt/block.dws?53dce9f31129de09323829ceb93bb637c5f6e2b6877fc89a72216d42e0c86c3c.htmThe "Value Out" amount of 1489.6eqt rings a bell as the amount I had, so maybe a clue there. (It was several years ago that I gave up on it, as the value of eqt plummeted, long before coin-exchange closed, & I had written it off).
Of course, now that it's being swapped for aluna, if there's any way at all of recovering this eqt within the wallet, I'm keen to get it swapped for something with a bit of promise.
50 cent, if I download & install the new wallet, would that not overwrite the existing wallet, with a new set of keys / receiving address? I'm being a little cautious with how to go about this, as I don't want to overwrite anything.