0x80070570 on install of Win7 x64 on Plextor SSD Asus P7P55D-E Pro

I'm at my wits end here and I have no idea what to do next. I like to think of myself as someone who can solve most computer related problems but this has me stumped. I've browsed through the forums and tried all the solutions I can find [which I'll mention shortly] but it has all been to no avail.

In short the story is I had a decent system running on an asrock mobo and the mobo failed. So i bought the asus board to replace it and instead of doing a repair I wanted to run a clean install. It's been nothing but headaches since.

Specs:
Asus P7P55D-E Pro [using Marvell 9123 Sata3 controller] with i5 760
128GB Plextor Sata3 SSD
8GB Mushkin blackline ddr3 [currently at 1333MHz]
Windows 7 Ultimate x64 on a kingston 8GB usb key

What I've tried:
-Completely wiping the SSD with killdisk
-installing on an unallocated partition
-partitioning the drive then installing
-putting the SSD in each of the two marvell ports
-AHCI mode and IDE mode
-rebuilding the install file on the USB key [twice; once manually and once using the win7 USB DVD download tool] [I unfortunately no longer have my physical CD... though I can still find my Vista CD, not that it does me any good]
-putting the SSD in the intel SATA2 port
-installing the marvell drivers first [I've tried 3 drivers: Marvell 9123-9120_V1001042 from asus website; Marvell 9123-9120_V1001032 from mobo driver cd; marvell_9xxx_1.2.0.1019 from marvell website]
-installing with 2GB ram... 4GB ram... and the full 8GB ram
-plugging the USB key into several different ports

I just don't know what else to do short of returning the mobo and buying a new one [or buying another copy of Win7...] I've used the usb key to install win7 before and it worked fine. I should have just repaired the installation from the start. That probably would have saved hours upon hours of effort.

As for the install. It would lock up around 20 something percent showing error code 0x80070570 [the file may be corrupt of missing]. After using killdisk to wipe the drive the install now consistently makes it all the way to 46% whether I load the marvell drivers or not.

Does anyone have any suggestions? [or further questions for clarification?]

Eric

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I should note this [and i bet this has something to do with my issues]

My USB device is showing up in the BIOS as a HDD. So when I select boot priority it's listed under the HDD. So to boot from my USB key I have to set it to boot primary from HDD and then set the USB key as HDD 1 [and I set my SSD as 2]. I should probably make it so that my USB boots as a removeable device instead of a hard drive... that might fix the issue... but I don't know how.