Solution for A Particular WiFi Access Point Not Visible
Imagine the confusion when your WiFi network is showing all available WiFi access points in the neighborhood except the one you want to connect to, adding more confusion - the same access-point is visible and connectable from other devices. Since, your WiFi access-point is visible from other devices and your WiFi client can see other access-point we can be sure that the two particular devices are working fine and are only having issues communicating to each other.
I recently encountered the same with my TECH-COM USB Wireless LAN Adapter, and the issue was this particular USB adaptor not able to work with WiFi channel 13. I even tried changing the WiFi channel properties by navigating to "Advanced" properties tab but this one simply refused to work. To get things back to a working state, I had to change WiFi channel back to 6 at the WiFi router.