Got my newly built desktop up and running!

Now I'm trying to capture video from an old Sony DCR-TRV120. I purchased a firewire to usb adaptor, but every time I plug it in, I get a notification that the usb isn't working. I can plug other stuff into it, and it works fine. I tried plugging into other usb ports, but same response. I even got 2 of the adaptors, and same story for each of them.

should I try a firewire to thunderbolt adapter and see if that works?
what software do I need? I am on Win 11. Everything I read says that the modern video capture software doesn't work with old tape recorders. I tried downloading sony's PlayMemory's Home, but the software couldn't detect the camera, I assume because the computer wasn't recognizing the usb connection.

I did something similar a few years ago. The only way I got USB to work was finding an old laptop with XP on it and burned the media that way.

Probably the easiest thing to do is get a USB RCA adapter and connect that way, assuming you have the RCA adapter for the camera.

I don't think the camcorder has rca ports/jacks.

It probably looks like a headphone jack. The cable looks like a headphone plug on one side and red, white, yellow RCA on the other. This is what mine looks like.

Yes, I have that. I was thinking the individual ports on the camera itself.

For connecting to a converter, your camera has an S-Video port. If you can't get the I.Link (FireWire) interface to work, that's what you would want to use as the picture quality is superior to the RCA interface. I took a look on Amazon and there are converters with USB out or HDMI out. If your PC has HDMI in, I would use that interface. Otherwise pick a USB version similar to the one linked below. I just did a quick search just to give you an idea of what's available. If I were buying, I would do a more extensive search to get the best quality within my allotted budget.

Video to Digital Converter

From what I've read on the FireWire interface, if your PC doesn't have a FireWire port you would need to use the Thunderbolt to FireWire adapter mentioned in your OP.

I have been slowly digitizing old videos. It took some trial an derror to get the right combo of stuff to work. Here is what has been working for a while now:

Play the video direct from your camera or hi8 player if you have one.

Connect the composite (YEL RED _WHT) audio and video cables to a 'composite to HDMI converter'. They are $10 from amazon. I went back in my order history, had mine since 2018. They don't sell it anymore but this one looks exactly the same except for the color of screen printing - https://a.co/d/3yurBnS

Then connect the HDMI cable from the converter to an HDMI to USB capture device or dongle (about $10 to $20).

Then I use OBS to record/digitize all my videos and even bring in a graphic for a title page etc.

They make a composite to USB converter. They run about $50 and up. I have not used one. I imagine it works just fine. I already had HDMI to USB converter so I didn't go that route.

Keep in mind FireWire is the only way you'll get an exact digital copy of the original video. Otherwise you're going from digital to analog back to digital.