Try to setup "Allow windows to turn this off to save power" The details can be found in this link,

Vista: Sleep & Loss of Internet ...Management setting for my Ethernet Card to select "Allow windows to turn this off to save power" I do not lose my Internet connection when returning from ...
http://www.chicagotech.net/netforums...c15cf5 19517f


Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
"Windy George" <Windy George@discussions.microsoft.com> wrote in message news:10194EAF-0AEB-4155-99B3-98AE83EB11E1@microsoft.com...
A scheduled task is configured to wake the system in order to perform. This
task will requite that a network connection is available. Before the system
goes to sleep, the DSL connection is running but it is lost when the system
goes to sleep and does not reconnect when the system wakes to perform the
scheduled task.

Is there a way to open the DSL network from the task scheduler?