I'd normally reset the network, flush TCP/IP and DNS and if that doesn't help uninstall and install the Lan card on your computer. If that doesn't help I'm honestly out of ideas. Maybe @Squirtle breh can help.
Most routers have at least an administrative website, for your local network; can the desktop get to the router home page at least. Also not sure if your desktop is wireless, but if possible can try to see if with a long wired cable works first, then if successful connection, then switch to wireless. Most default setups are fine... but we're also assuming you're not using a tricked out setting like whitelisting only approved mac addresses in the house or custom firewall setup ... etc.
https://www.yellowpages.com/spring-tx/mip/chads-computer-repair-and-services-480716327 No reviews, but they are local AND open 24/7.
Put your phone in hotspot mode and join your computer to the phone network. If you're still having issues, there's something wrong with either browser cache/cookies or your network settings on your PC, not your wifi router. Whatever web browser you use, google that and 'clear settings'. Reboot when you're done.
I tried to upgrade the firmware on my router with the latest version. I downloaded the file, unzipped, verified the MD5 checksum after download to what the site said it should be to ensure file integrity, and then attempted to upgrade the firmware from the administrator page. It gave me an error. I gave up. ****! On top of that, I found out Microsoft will not support my CPU with Windows 11 even though it's Intel(R) Core(TM) i7-7700K CPU @ 4.20 Gigahertz . Are you ****-ing kidding me? Double ****! My DirecTV HD receiver in my office/main viewing room...the local HD and other HD channels are giving me "signal 771" errors even though my DirecTV HD receiver in the master bedroom picks up the channels fine. It was working fine a few days ago and before. Nothing changed. Multiple resets...not fixed. Are you...mmmkay drugs are bad...kidding me? Triple ****! Life is exhausting sometimes.
Perhaps you need the Trump version? Firmware is nasty! Microsoft is ugly! DirecTV is horrible...absolutely horrible!
I've cleared cache, flushed dns, removed chrome, done a full network reset. I'm online, but only to a few websites. I've looked up and tried 20 different solutions and while I got back online, none of the other solutions has done anything to stop the nxdomain error to keep coming up. And the network reset took two hours.
They sent a new router and that seems to have got the websites back in order, but there is definitely a lag in streaming. On hold with ATT to see about that part, but appreciate all of the help!
Got a new router and the same thing came up after a couple hours. On hold again for dozens of minutes again
It almost sounds like a problem I had years ago where I was going to a bad (maybe rogue) DNS server that was set up on my ISP's network and I couldn't get to sites. My problem didn't resolve until they finally figured it out and took it down. I would hate to think that is what is happening to you. A rogue DNS server could be a man-in-the-middle type attack where your computer was hit with a virus that changed your DNS settings. Have you verified your DNS settings are correct? It seems far-fetched but I don't get what is happening there otherwise. It seems you have eliminated any kind of router hardware problem. A little light reading on it: Rogue DNS Attacks – A less understood hacker attack | Bobby Cahill
Wifi router is different than the one your isp sends you. Those things need to be replaced after 5-7 years. If it's not that and you only have this problem with laptop, then run malware and virus scanners. Avast is a good free virus scanner from when I remember using Windows.
