Model : Archer D5

Hardware Version :

Firmware Version :

ISP :

Every time i switch off my router and switch it back on, it just stops working, all the lights are glowing but the internet LED is ember. It works just as new after i restore factory default and reconfigure the whole router again sometimes it just starts working if i reboot the router. It has been a consistent problem for the last 2 months.

I have also noticed that the internet LED glows even if the cable is removed from the slot. I tried updating the firmware but there were no changes in the error. Someone please help !!!
here are some details of the router:

Model : TL-WR740N
Firmware Version: 3.16.9 Build 160325 Rel.61670n
Hardware Version:WR740N v6 00000000