well the modem was Nokia Siemens residential 1600 , it had no usb port, and my ubuntu 10.10 didnt have the ethernet driver to recognize the modem through ethernet connection, the whole issue started since my wifes laptop which automatically connected to the wifi was not powering up, when i showed it to the local hp service center they diagnosed that the power adaptor was to gone and needed to be replaced...and the replacement would cost INR 2k, when i contacted the IT dealer near my locality he expressed the view that maybe the same adaptor could be repaired...and yes it was repaired for INR 450/-. anyway upon booting up the system it was pretty straight forward to know the wifi pass word.

the steps (of one among several methods) are as follows (windows 7):

1. From the start menu goto  control panel-network and internet-network and sharing center-view network status and tasks-manage wireless networks
2. In the manage wireless networks window, select and right-click on the network name for which you want to know the password, and then  click properties.
3.  click the Security tab, and click the Show characters check box.(the characters appearing in the network security key is the wifi password)