Why my dlink router freezes all the lights including power

I had problems in internet connectivity. Ultimately approached the vendor dlink, and as the device is in warranty period, i was given exchange of modem of the same brand same version.
i had checked the line both modem and phone, and everything is working fine. But, the strange problem for a few days that modem stay still with all lights glow. The internet light also not binking showing frozen status.
i had to power off to reboot the same, it works and then the same problem of freezing occurs. when i trouble shoot the same, the trouble shoot does not find any problem, as all lights are glowing. But i could not browse.
i do not know the possible reason for this behaviour. Is there any fix, immediate at that ?
i scanned the pc with avast with no virus found in bootscan.
As the replaced device is new one, i do not think that there is anything to do with the modemwifi. it is dlink 2730u, india model having 1.1 version.
what would be the possible fix. experts pl

Hi, i have enabled my router logs and find that herewith.
i disabled ddns, as it was not my service provider address in the router, instead, i changed the dns to google dns for security purpose.
i have changed the psword for both admin and user for the router, but it says wrongly in the log.
The logs are dated 1970, but take that as occured todate