Nokia Siemens 1600 router doesn't work when Wi-Fi is enabled

Hi Everyone,
I am facing a problem with my Nokia Siemens 1600 router ( 4 years old).
Scenario 1:
Ethernet Cable plugged to the router + Wi-Fi is enabled
When the Ethernet cable is plugged into the router and also when Wi-Fi is enabled (Wi-Fi enabling/disabling through http://192.168.1.1), all the LED's except Power LED goes off. Then DSL will be blinking for few minutes and it will turn off... again it will blink and goes off.. this cycle repeats without making any internet connection.
Scenario 2:
Ethernet Cable unplugged from the router and Wi-Fi is enabled
When the Ethernet cable is not plugged into the router and when Wi-Fi is enabled modem will be connected to Internet and I can surf the internet through my smartphone without any disconnection.
Scenario 3:
Ethernet Cable plugged to the router and Wi-Fi is disabled
When the Ethernet cable is plugged into the router and Wi-Fi is disabled then I can access Internet from my PC without any interruption in connection.
Bottom Line of my problem is I cant use Wi-Fi through my smartphone and Internet through PC at the same time.
Either one must be disabled to get the other working.
Please help me. What is the Problem here. I couldn't find out.
I am unable to get any help from BSNL people. They simply closes my complaint without solving.

Hi friends, can someone help me on this. its quite urgent.

Reset the modem and check. Hope you tried PPPoE mode.

meetdilip said:

Reset the modem and check. Hope you tried PPPoE mode.

Click to expand...

Thanks for reply. Yes i tried reset the modem many times. but no use. and yeah I am using PPPoE mode. I went to exchange and checked the modem. The technician doesn't have much knowledge i would say. He simply asked me to buy a new modem.

Ask them to connect using their ID and password.