automatic internet connection

i have bsnl broadband and adsl modem of siemens
earlier my internet connection used to be automatically connected whenever i switched on my computer and modem ,but now i have to always go to 192.168.1.1 then configuration then internet and then connect to get connected to internet whenever i switch off and then switch back the modem on.

can anyone tell me how can i get my modem automatically connect as it earlier used to connect to internet automatically??????