Cannot open the modem webpage

Hello,

this is kajal,I have a bsnl broadband conection,my internet is working on my laptop with automatic detection but not on my pc. Internet was working on my pc after putting the ip address but as soon as i connected the internet cable with my laptop(which was on automatic settings) the internet stopped working on my pc when i connected the cable back to my pc.. now i don't know what is the problem ,whether the settings of the modem has changed. I am not able to open the modem webpage neither on my laptop nor on my pc. please suggest me what can be done.
thanks and regards
kajal