Can anybody advise what is causing this? In my 30 years of constructing and fixing computers, I've never seen or heard of this problem before.

My wife's Windows 10 desktop and Android phone both stopped identifying our wireless access point as recently as yesterday. (The Wi-Fi router is around 8 feet distant in the same room). The strange thing is that when I check available networks, both devices can "see" all of my neighbors' networks in our block, but not our own. Her phone works regularly in all of the outside Wi-Fi hotspots we visit, such as cafés. My two Windows 11 desktop PCs, my HP tablet, and my Android phone all function well. I have made no modifications to the hardware, software, or configuration that may explain this. I tried resetting the network and converting her PC's Wi-Fi adapter to a USB Wi-Fi dongle, but the results were the same, and this didn't explain why it was also occurring on her Android phone.

It does not seem to be a hardware problem, therefore it must be software, and I am wondering whether it may be caused by a virus or malware. I can't think of anything else that would prevent two devices from seeing the same Wi-Fi network.

I'd appreciate any recommendations.