10 ways to troubleshoot and fix any Wi-Fi problems you're encountering

When you encounter Wi-Fi problems, you can try troubleshooting your network or devices, check with your internet service ...
Ars Technica

[EDIT]Computer on 5GHz wireless cannot see computer on 2.4Ghz network, and vice-versa

Here's the story: My home network has three computers attached to it. One has a wired connection to the router (an Asus RT-N66U), one has a wireless (5GHz) connection, and the last a wireless (2.4GHz) ...