Earlier I used Windows 7 and the modem used to work absolutely fine. Even when it got disconnected it used to reconnect automatically without any trouble. But then I installed Ubuntu 11.10 on dual-boot and set up the modem connection properly but the modem now disconnects much more frequently (earlier it disconnected once in 5 hours or so and after Ubuntu in 5 minutes!).

Also once disconnected, it does not reconnect even when I have checked the "Connect Automatically" button. I have to restart the system to reconnect it. I the clean installed Windows and modem works perfectly fine again.

What is the reason for this and how can I solve this? I really want to use Ubuntu but due to this problem I can't.