Audio Crackle/Stutter, Sigmatel, iTunes, Alps Electric Touchpad, Vista Ultimate, Vostro 1400

Hi, I recently posted in another thread, but decided to create a new thread with all the new information I have discovered.

First, these are all the driver versions i have for the various hardware that I have read might be causing the audio crackle:

Sigmatel stac 92xx c-major hd : 6.10.0.5609 released 9.7.207

Dell Wireless 1505 Draft 802.11n WLAN Mini-Card: 4.170.25.17 released 10.12.2007

Touchpad: 7.1.102.7 released 8.24.2007

The problem:

My audio crackles or stutters what seems to be randomly and at times when I am doing nothing on the computer, when I just have music playing.  This system is new on system exchange. I previously had audio problems with an E1405 with the same sound and wireless cards, but XP Media Center Edition. The audio problems on that system were actually somewhat different in form, that is, they happened predictably in intervals.

The audio seems to primarily crackle with iTunes, but it might just be that I use iTunes primarily and thus haven't observed it with other players.  I am however sure I have heard it with Windows Media Player, but i haven't really heard it with Dell Media Center, although I have only tried the Dell Media Center a couple of times.

A cool thing about iTunes is that it allows users to see and play music from others with iTunes on the same network.  My roommate has played music on her computer from my computer and there is no crackle, meaning there is nothing wrong with any of my music files. 

When I navigate through windows using the touchpad, I get an occasional audio crackle, and peculiarly enough, when I start the itunes program the speakers crackle subtly in sort of a pulsating fashion.  I can also get the crackle to happen when I maximize iTunes from its minimized place on the start bar and when I drag the cursor across the opened iTunes program.  When, however, i play music, I can no longer get the crackle to happen on command with iTunes, that is, maximizing and dragging the cursor across the program no longer produce a crackle.

These are the things I have done to try to eliminate this crackle/stutter:

1) Got an entirely new system (with refurbished parts, of course... go environmentalist-ically validated capitalism!)

2) I read that the Dell Draft N mini-card causes interference with the audio, so I disabled it, uninstalled the drivers, installed an older driver for the wireless card, and removed the card from the computer completely-TWICE--all to no avail.

3) I checked the "disable enhancements" box in the sigmatel controls

4) I have the most up-to-date drivers

5) Reinstalled the driver for the audio several times, deleting previous installs before reinstallation

6) Let windows vista install its high def audio drivers, which didn't work at all

7) I have the most up-to-date BIOS version

8) I have service pack 1 now--no effect on the audio

9) I have disabled the "a" band on my network card.  i am reluctant to say that the crackling seems to have lessened ever so slightly, but the crackle is still very clearly there.
10) Disabled the windows "beep" in the device manager

11)Just in case anyone thinks this is the problem: iTunes audio enhancements are inactive

In a search unrelated to my audio issues, I randomly stumbled upon an article discussing the Vista service pack and it stated that Sigmatel drivers have caused problems with Vista.  I am wondering, barring any actual solutions to this problem without having to buy new hardware, if anyone thinks that buying an Express Slot audio card will fix the audio.  If so, can anyone recommend one?

Thanks for you help!

Jeff