Have you ever tried to configure your ADSL Modem to automatically connect to the internet without requiring to connect from a computer? Are you a BSNL Broadband user? I have played without success with the ADSL Modem manual before I found this gem on BSNL site.

Link

Few Tips:
You may not want to keep the default IP address of 192.168.1.1 for the DSL Router. For example if you change the IP address of the router to 192.168.5.1 then ensure that the IP address of your machine is in the range 192.168.5.* and your gateway is 192.168.5.1.

You can and should change the default password for your modem for added security. It is available under Admin section. Commit and Reboot after the changes.