@ animishprime
how do u connect to net from day 1? [i.e. since the day u got the connection]
if you are using it thru USB, then stop using it thru USB! its gets disconnected frequently...same thing has happened in most cases for members here.
If u dont have ethernet onboard, or if you have one, but not able to connect thru it, then u will have to buy a NIC - Network Interface Card..which costs around Rs. 300-500. then connect ur modem thru that and check..
if problem still persists, then call BSNL exchange, ask them to check line.