windows 7 freezes during shut down

[Mohnishgs]

sometimes when i try to shut down my pc, soon after the "shutting down" screen the computer hangs
this happens when i shut down while the net is still connected
or when i try to connect to the net and it gets stuck on the "registering your computer on the network" screen and after some time it gives me some error and redials in 30secs.

This was the error reported in event viewer:
CoId={E9F17D23-3EF7-4CE3-9C98-1E46F157844F}: The user RattleSnake-PC\Rattle Snake dialed a connection named Broadband Connection 1 which has failed. The error code returned on failure is 0.

though the connection fails to establish the network icon in the system tray says iam still connected even though iam not and when i try to shut down the pc it hangs in the same screen
this connection failure usually occurs when iam connecting to the internet the second time in the same session

someone please help.......

p.s. atleast tell me what processes i need to end so that the system shuts down properly