There really is not much else to say about this, but I am still reviewing things in the small hopes I find something.
I double-checked the hardware and device ids, and even had a look at the driver's .inf to see if they all correlate, and they do. What you have really is the proper driver for it.
Since we're in a nothing to lose situation here, give this driver version a try, although I do not have high hopes: Driver Details | Dell US
Perhaps the motheroard is faulty in regards to the network circuit.. I dunno. It would be a first I've even seen though, heh.
A wild shot in the dark here: Rename this driver to .BAK then reboot to test. If it doesn't fix the situation, rename it to original:
Another wild shot in the dark, because these seem well enough (but do share IRQ with Atheros) - try to see if there is an update to your AMD storage drivers, either at AMD's site or motherboard (MSI) site:
0: kd> lmvm PxHlpa64
start end module name
fffff880`00bed000 fffff880`00bf91a0 PxHlpa64 (deferred)
Image path: \SystemRoot\System32\Drivers\PxHlpa64.sys
Image name: PxHlpa64.sys
Timestamp: Tue Apr 24 13:26:29 2012 (4F96E245)
Translations: 0000.04b0 0000.04e4 0409.04b0 0409.04e4
I also noticed you have Norton Download Manager. I don't see any drivers for it, but we are dealing with network funk. Suggest removal as a testing measure.
amd_sata amd_sata.sys Fri Nov 30 04:00:42 2012 (50B875BA)
amd_xata amd_xata.sys Fri Nov 30 04:00:46 2012 (50B875BE)