I can't seem to find the link, but I had copied the text off for my own reference. If this works for you, its the original author who gets the headbang.

This totally transformed my 51!
The problem starts with the Windows Update for the Atheros a/b/g card. DO NOT INSTALL IT! It causes the mouse and sound to skip. I troubleshooted it noting that when my wireless was disabled, it worked fine, so I knew it must be a wireless issue.
Here's the solution (thanks to Ron at Alienware):
1- Download the driver for the correct Wireless card from the support site, depending on the wireless card they bought.
2- Remove the driver that currently is in use from the device manager and uninstall all related software for the wireless card. It should be the last item on the Add/remove programs, WLAN a+b mini-PCI module.
3- Reinstall the driver the customer downloaded from our website using the set up file.
4- After installing the software and drivers, go to Network connections and open the properties for the wireless connection, go to the Wireless Networks tab and UNCHECK "use windows to configure my wireless network settings".
5- Now run the WLAN program that installed with the driver, there should be a shortcut on the desktop. Make sure that " enable smart selection" is UNCHECKED. Then hit the REFRESH button and the wireless network should appear in the box below. Now create a new profile. Click " enable advance settings" and select the WIRELESS MODE that the router supports. For example if running a 802.11b select 802.11b as a wireless mode, if running a 802.11a or 802.11g select the wireless mode according to the one that he is using. Have the customer select " passive mode" in the SCAN MODE tab and have him select 50% or even 25% in the Transmit Power Tab. The Transmit power is directly related to the volume of the interference picked up by the speakers. If 50% still gives u the static noise lower it to 25% and test to see if you still have that noise from the speakers. The interference should go away after all those settings.
Note: in my case I downloaded the latest drivers from Alienware, and the application used to set the configuration was the "WLAN a+b+g mini PCI module" program I had installed from the CD that shipped with my Area 51m (new version.) This may already be installed on your computer, but I had done a reformat and fresh install of Windows XP Home.