just change the DataOne password.. i think that will stop user from loging in...
any way... for DataOne.. one thing u can try... that is.. turn on the Modem.. got to the control panel... that is *192.168.1.1/ ... (hope u have UT300R2 type modem...) now there go to the Setup then click the the connection what u have... in there u have a option call On Demand....
*img365.imageshack.us/img365/4813/003dl.th.jpg
turn it on... click apply... the go to Tools then System Commands... there click Save All.... turn ur modem off... then turn it back again... wait for the PPPoE lite to come up... if it comes up then i dont know any option for doing what u wanted... its plug n play... but if it doesnt... that means the u have the option what u wanted (Dialer)....
now if u have winXP then, go to the Network Connection... cr8 a new connection... connect to the internet, set up my connection manually, now the second option Connect Using a Broadband connection that requirs a user name & password... give the ISP name BSNL BB, put ur user name & password... now dial...