Windows 7: Wake on Lan Setup Problem

I am trying to setup Wake on Lan on my pc so that I can remotely turn it on and remote to it. I mainly want to do this from my Motorola Droid android phone.



I have wake on lan turned on in the BIOS.
I also have "Allow this device to wake the computer" checked in the onboard NIC's power management.

The problem I am seeing is that, the wake on lan only works for about the first 2 minutes after the computer is shutdown then it no longer responds.

I am using dyndns.org to host a domain that forwards to the WAN IP of my WRT54G wireless router.

The router is running stock firmware.

Can anyone help me figure out why it only responds for a short while then stops working?

Anyone have any ideas on how to solve this problem?