I’m going to guess that the Comcast WiFi has only current encryption methods, and not the older kind, and that your laptop might only be able to handle the older kind, it’s possible a driver could help but encryption might be done in hardware for speed.
If that’s the problem and nothing else works, you can get a cheap WiFi ‘access point’, plug that on a wire into the hib on the comcast, and set it to the older style encryption then connect your old laptop to that.

USB wifi antennas (Amazon link) are cheap and easy as well.

To answer the question, there’s 3 places you’d generally get drivers

1) Your operating system gets new drivers with updates, so may take care of it for you
2) The manufacturer for your wifi antenna should have the latest, sometimes they’re built into another device though (so #3 is generally easier)
3) The laptop manufacturer should have fairly updated drivers if it’s a major company, usually doing a search for the model and the word “drivers” will take you straight to a page where they can be downloaded and they should have some instructions for installing them

I don’t think drivers will solve your problem, so suggested the new antenna above, but if you want to chase them down, those are the places to start.

Good luck.

Did they change the equipment?
Sound more like you need ^ a new antenna !

No, they did not swap out the equipment that they supplied me as an end user. It is a cable modem with a built-in router for WiFi.
But they clearly made a change at their central location, because the name (SSID) that I had defined for my local network disappeared and went back to the default name. I noticed that my SSID was no longer showing up as an available connection on any of my devices, so I called tech support. They re-defined my SSID and password into their system, but now it shows up only on my iPhone and iPad, which can connect just fine. The tech guy did say that “older” devices would not find the connection.
So I’m wondering if it’s just a matter of downloading new drivers for my laptop.

@funkdaddy I’m using USB WiFi antenna made by Logitech. Maybe I just need a new antenna, eh?

A couple of options:

Logitech keeps drivers rolling out for a while, you can check their downloads page, search by the model and that will let you make sure you have the latest. If you’re on Windows, I’d guess it’s probably already updated.

As far as Comcast, I’d guess they switched to a central management system for all modems, but I’m a little surprised you didn’t get a new one sent in the mail. You can probably access settings through their website if you log in to your Comcast account. That’s just a guess, I don’t know about Comcast specifically, but a lot of providers are going that way.

Looking at their documentation, it’s kind of all over the place with a dedicated app, an in browser manager, and managing settings through your account as mentioned above. So it’s tough to find specific steps for your situation without seeing more.

When you’re logged in to whatever method works for your setup, it should have an option for “encryption” or “security” or something similar. If so, try different settings there, restart the modem, and see if you can connect. It’s slightly more complicated than that, but not much.

Personally, I’d probably order or borrow another wifi antenna and try that if the current one is more than about 5 years old. They’re handy for other things as well, and relatively cheap as computer equipment goes. It’s also a piece that’s under your control rather than the cable company. The more you can leave default on their stuff, and still have everything work, the better really. They reset that stuff way too often and without warning.

Good luck.