Well,
i have installed windows7 beta in one partition of my computer but unfortunately this operating system does not recognise the driver which comes with the modem CD.
THe same problem i am facing with linux (obuntu) operating system, how can i install tata USB modem in obuntu.

What is the make / model of the that Modem ?
Hope you are taking about TATA adsl or is it TATA wireless modem based on CDMA 1x ?