I had exactly the same problem. I got it replaced. And bro dont tell them ur OS cos ones i said mine is win 8, they were not willing to help cos it seems the device is not compatible and they dont care even if u prove them that device is faulty. Theyl ask you to wait till sim is activated even tho it has nothing to do with the problem.Guys I have a small doubt. I bought an Evdo device yesterday in Chennai and got the Prithvi device. When i connect the device to my laptop it gets detected for a few seconds and then disconnects . This process repeats. My RUIM is yet to be activated. Have I received a faulty device or will it work normally once my account has been activated
So dont waste more time, just ask them to check with their systems and get it replaced. If u r using the Mandeveli branch, take a formal letter requesting replacement and a xerox of the bill.
PS: Prithvi Ue 100 works on my win8 and the chennai bsnl guys wont help anyone with win8 cos according to them win8 is "unstable". xd