Hi Nithinks,
I faced the same problem when i first installed my modem. Use the following steps. I hope itshould solve your problem.
1) turn off your comp. - switch on your modem- then turn your comp on.
and yes do not forget to check out if all your connections r according
to the manual.
2) your XP os will automatically detect the modem.
3) Then go to
add new hardware tab in the control panel of your pc.
4) place the modem software cd and follow the instructions to install the
modem.
5) once your modem has been installed right click on your My Computer
icon and select the properties.-- then go to the hardware tab -- then
select the device manager tab and go to th modem and right click on
the modem tab. then check all tabs to find something called wait for
dial tone. deselect it.
6) now prepare new connection and ask for the no. to be dialled. user name -- your phone no. --- password --- wahtever u like -- and regardin the no. to b dialed get it checkedform your local operator coz it varies from location to location.
now u r ready 2 use your modem.
try it out. hope it works

. worked for me though...
Regards,
Pratik