Belkin f5d7632-4 version 7000uk hangs

[sunny9616]

If I use it only as a router, it works great without any problem. But when I plugin the adsl cable and use the modem as well it hangs within few hours. I have 2 lines from 2 different isps and it hangs on both lines as well as on different pcs.When in hanged status following is observed

Ethernet leds are off even tho cables r connected
Adsl and internet leds stay on even if I remove the adsl cable out
cant ping the router/replugging solves the problem for some time.
even if im not using the conenction at all like in overnight it will still hang withing 10-12 hrs
I called belkin support they got me to update fimrware to 7.0.0.27 but still same problem.they replaced the router which has same model and version (7000) and still the same problem even in new one.Firewall is on i have tried modulation type etc but not sucess.

Belkin support is polite, helpful, impressive but not effective in this case.