I do have several copies of the keystore (UTC) file in addition to knowing the password and all that. The wallet I used was just called "Ethereum Wallet" and "Mist". I guess the developers have labeled this stuff as "deprecated" and they no longer support it. I originally got it from github.com/ethereum/mist/releases.

Can I just import my keystore file into a new, modern wallet and gain access that way? Like I said I've been out of the crypto space for a long time and forgot almost everything about it.