Help Me To Solve Ip Problem


I am using BSNL BB with starlite MT882 adsl modem.I have 6 computer(Win XP) connected through LAN with a client computer (Not server) having ip and others have option "Obtain IP automatically. I have connected ADSL modem via LAn port to the switch i am using for LAN.I cannot access (to configure modem)as it says this IP is used by others.But if I cange my computer IP to 192.168.1.X then I can access the modem configure page but that time I can not access other computer through LAN.More over if i keep the BB connection idle for sometime the machine needs restart.