Issue with Linksys wrt54g router

[sam1]

Hi everyone, I am facing a strange issue with the router mentioned. Whenever I connect the cable modem to the router, it stops working after about 2 mins. By that I mean, destination (192.168.1.1) becomes unreachable while pinging. If I disconnect the modem and restart the router, I can ping it, access the UI as normal.
The version of my Linksys wrt54g router is version 7 and my cable isp (alliance broadband, kolkata) gave me a cable modem which I used to connect to the router, thereby enabling wired as well as wireless access on multiple devices.
I have flashed the firmware, reset the router 5 times to its default settings, but to no avail - everytime I connect the modem to the router, after around 2 mins, the router becomes unreachable.
If anyone else has faced this issue and has been able to resolve it, please provide some advice. It will be highly appreciated.
p.s. - it has been working fine for about 1 year, since I setup the router this way, so it's not some config change that is causing the issue.

 

[whitestar_999]

Maybe the hardware is failing,wrt54g v7 is quite an old model.you can try accessing 192.168.1.1 using mobile device while no other device is connected.

 

[sam1]

Maybe the hardware is failing,wrt54g v7 is quite an old model.you can try accessing 192.168.1.1 using mobile device while no other device is connected.

Tried that several times, no issues at all. Only when I connect the RJ45 cable from the cable modem to the router, it becomes unreachable after about 2 mins. It doesn't switch off though, all the lights are on as they should be, including the power and LAN connection indicators.