BleepingComputer.com: Internet Connection Keeps Dropping After Idle

I have been experiencing dropped connections with the Internet after my Dell 4550 (Windows XP SP3 with DLink Air Plus DWL G250 Wireless G Card Rev. is idled for any period of time. I am running Comcast with a DLink DIR 655 Extreme N Router (Hardware Version: A3, Product Page: DIR-655, Firmware Version: 1.21), and have recently upgraded the firmware on the router - no upgrades are available for the G250. Comcast insists that their modem is running fine, but I am only losing Internet connection - I can print to my HP 1022NW printer any time. However, when I restart the computer, my connection is restored. I do have two users on this account, but this wasn't the case before the re-image took place.

In addition, I cannot access the DLink icon in the System tray to make any changes to the G250. I am taken directly to the Windows Wireless Connection Properties. Finally, I did re-image this machine about 2 weeks ago, but my connection issue was a problem before that time.

Any suggestions that can be offered would be appreciated.

Matt