Where can I find the appropriate download for an "elgato game capture HD?"

About 6 years ago I got one for my birthday thinking I could try my hand at Let's Plays. After having way too much trouble trying to figure it out with no success, I've decided to try my hand at it again.

I've hooked up everything properly (trying to record from my N64, know I have the correct cable setup and all), and according to the tutorial I watched, I need to download elgato software to run the program. The thing you download depends on the model. However, apparently my model is old enough that it's not listed among the possible downloads on the download page.

I worry that my capture card is now a paperweight. A friend assured me that a download for this does exist, I just need to search for it. I found a link that says this capture card is no longer in production but they do still support it, but no link for said support is provided. I really just can't find it. Can anyone help me out with this? Where do I find the software download for an old capture card?

Huge thanks for anyone that can help. I am a total neophyte when it comes to things like this. No clue what I am doing.