Your ASUS RT-N14UHP is on a very old firmware.
The latest firmware for RT-N14UHP is 3.0.0.4.376.2671.

Direct Download Link:
RT-N14UHP 3.0.0.4.376.2671

Note 1: Do not run the firmware upgrade through WiFi. It may brick your router. Always run the upgrade through an ethernet (LAN) cable.
Note 2: It's also a good idea to restore the router to factory default before upgrading the firmware.

PS: I can't promise that the newer firmware will fix your issue, but it's worth a try.

This post has been edited by sHawTY: Nov 8 2014, 07:46 PM

If you're still facing the same problem even after upgrading the firmware, do post your problem in the link below.
That thread is officially managed by an ASUS Malaysia representative.
https://forum.lowyat.net/topic/2651405

This post has been edited by sHawTY: Nov 8 2014, 07:43 PM

Administration > Restore/Save/Upload Setting > Factory default > Restore > OK
No, you don't have to set up everything again.
Before restoring your router to factory default, go to the Administration > Restore/Save/Upload Setting > Save Settings > Save.
Remember the location in your harddrive on where you save the settings.

Once you've upgraded the firmware, go to the Administration > Restore/Save/Upload Setting > Restore setting > Choose File (locate the file you saved earlier) > Upload.

Note: You can choose to restore the previous setting, but setting up the router again from zero is a much better choice.
RT-N14UHP doesn't support 5GHz.

This post has been edited by sHawTY: Nov 8 2014, 11:24 PM

It's actually not that hard.
The onlything you need is your UniFi PPPoE username & password.
If you don't have them, you can get it from UniFi helpline by calling 1300-88-1221.

Once you have them, the setup would be pretty straight forward as ASUS router is one of the easiest to setup when compared to other brands.
You need to learn how to set it up yourself so the next time you upgrade the firmware, you'll remember how to set it up.
Unlike other manufacturers, ASUS frequently release firmware updates for their networking products to fix bugs & add new features..
My 3 & ½ year old ASUS RT-N16 still receive firmware updates.

If you want to make things easier, before you restore the router to factory default, just take screenshots of every page & tabs in the router's WEBGUI.

Use a channel that is not used by your neighbours so it doesn't conflict with your own WiFi.

http://www.maketecheasier.com/find-best-wifi-channel/

......
If your PC doesn't have a WiFi adapter, then offcourse the PC can't detect any WiFi signal.
Use a laptop instead.

If you don't have a laptop, just search for an android / iOS WiFi channel scanner.

Yes. Do let us know if you're still having problem.

By the way, I remember your previous post saying that you've set-up the router from the start.
Does that mean you've upgraded the firmware?

This post has been edited by sHawTY: Nov 10 2014, 09:03 PM

Change the Channel Bandwidth to 40MHz only.
See if that helps.

After pressing Apply, reboot the router.

N Only.

If the problem persists, I suggest you to post it in the official ASUS Malaysia Networking Thread.
The thread is handled by official ASUS Malaysia representative.

Link: https://forum.lowyat.net/topic/2651405