I am having trouble finding a USB Wireless Network Adapter (made by Belkin, as one possible supplier) that is compatible with Windows 7 (if not Windows 8 and 10, ideally). …Are these things obsolete now? If they are obsolete, what has taken their place to access Wi-Fi on a PC?
I’d guess close to 100% of mass market PCs being made today have a built in WiFi Adapter.
I found these on Amazon (after going outside Amazon and refining my Google search). Do you think one of these first two items listed are what I need?
You are probably right that they are not in demand as they once were. I have an odd set-up in my house, and I could use one now.
I have bought several of them in recent years. (For non-WiFi Raspberry Pis.) And yes, most if not all also work for MS-Windows.
If you can’t find them you’re just not trying.
Caution: The concern is NOT if they will work with MS-Windows. The concern is if they will work with specific versions of windows. I am surprised Belkin is a well-known brand; yet, it does not appear they continued to market this item. One must wonder why a well-known brand would not continue to produce this particular gadget.
It’s not hard if you understand all that jibberish about dual-band, etc. I just want to be sure I am buying the right thing. It’s MY headache when it doesn’t work and I have to fight to return it…not yours.
I don’t understand what’s so hard. Amazon has dozens of them, in a wide range of prices and from many manufacturers. The listing at each link below includes comparisons with other similar products.
As for “fighting” to return things, I’ve always found Amazon’s return process to be simple and painless, although for a $7.50 item, like the cheapest of these, it may not be worth bothering with.
I don’t think that there’s really much to wonder about. It’s almost undoubtedly because, as has been noted, onboard wifi adapters are pretty much standard now on mass-market PCs. I’d guess that demand / sales for the adapters dropped off enough in recent years that Belkin decided to discontinue selling them. Belkin used to sell floppy disk drives, once upon a time, too. 
A “specific” version? MS-Windows 7+ is absolutely, positively, not remotely a problem.
Belkin bought out Linksys. That may be why they don’t sell networking products under the Belkin brand name anymore. Linksys sells many USB WiFi adapters.
They are still widely available from many manufacturers. I have several - one on my gaming PC which didn’t come with onboard WiFi, one on my Raspberry Pi, and one on my wife’s laptop because the built-in 2.4 GHz wifi kept getting dropped by interference from the microwave oven.
If Amazon returns are a hassle have you considered looking for one at a local Office Depot, Best Buy, Microcenter or even Wal Mart or Target? I see my local Wal Mart carries one.
I shop on Amazon a ton but if I think I might have to return something I go right to a local store.
I use the Broadcam NetXtreme 57 by Ralink. Windows 7 already has the driver for it so, when you plug it into a USB port, it installs. I carry it with me at work at all times in case I have an issue with connectivity and need an alternate way to connect a computer. It works great.