Broadband Dialup Connection hangs/freezes

Hi everyone,

I am from india I use Lynksys AM300 modem/router to connect to internet through USB cable, I use Bridged Mode Only setting in modem, and connect to internet from dial-up PPPoE connection that I made through Network and Sharing center. My ISP is BSNL. Since I upgraded to windows 7 some times suddenly I am disconnected from Internet, their is is no redial window, and when I click on network icon near time display (right bottom on taskbar), it shows status as connected under the dial-up connection and shows no internet connection on the network icon, when I click on disconnect nothing happens, and status still shows connected, nothing happens when I right click the connection and select either disconnect or status, but when I click on properties the window open. Even when I try to open Dial-up connection from adapter setting nothing open i.e whole dial-up system hangs.

After all above I have to restart my PC and after windows starts I can connect without any problem.

I have tried following thing but nothing changes
 - Updating modem firmware
 - Connecting through LAN instead of USB
 - Connecting through PPPoE from within the modem
 - Updating all drivers including modem USB
 - Tried resetting LAN/ NDIS USB device (USB Driver)

This never used to happen in XP or Vista, this is really frustrating, usually I go to office keeping my PC connected and ON for downloading and when I return their is nothing downloaded, I have tried google for past 5 days but no help please someone help I don't want to go to Vista or XP.