Windows 7: Problems booting an unattended Windows installation from a partition

I have been given the challenge to make a way to install Windows without any installation media and without having to even touch the computer while it's installing. So far I've made a .wim image with the help of this guide and I've made an Autounattend.xml file with the help of this guide. I put the install.wim image in the \sources directory on a flash drive and the Autounattend.xml file in the root of the flash drive, and it does exactly what I want it to - all except it's not on a partition. So I move it to a partition and add a boot entry using EasyBCD. It boots fine, but it acts like the Autounattend.xml file isn't even there. So right now I have the choice of hands free installation with media, or manual installation without media. My main question is why the Autounattend.xml file isn't working when I boot the same media from a partition. Any help is greatly appreciated.

Is this some sort of school project? I can't vouch for anyone else, but I would feel terrible if I gave you information that basically did the project for you.

Usually people do this with Windows PE. Have you checked it out?

Haha, no. I work in a computer repair shop and it's a challenge my boss gave me to work on during the slow days to explore easier ways of installing Windows.

I burned a winpe.iso disk as instructed in that first tutorial I linked to. I don't really understand what it is though. A little Googling tells me it stands for Windows Preinstallation Environment. Do you have a tutorial or something that will show me how to do what I'm trying to do?

I'm still confused as to why my Autounattend.xml file will work on a flash drive but not a partition.

Here's some info directly from MS:

What is Windows PE?

If you are going to install Windows on multiple computers with nearly identical hardware, by far the easiest way is to create a standard image, then using sysprep to prepare the system for deployment. When that is done, clone the drive to an external device, and just restore it on the new hardware.

If you are just trying to create an unattended install, you can easily do that by following some of the guides available on the 'net - and do the installs from a USB device. I know it's not an unattended install, but it's very easy and requires minimal input from you - but you will be stuck with having to install drivers; not a big deal for one-off installs, but a pain for multiple installs - which is where the beauty of the sysprep comes into play.

I'm not necessarily trying to install to multiple computers with similar hardware. At this point I just want to kind of create my own "factory defaults" where if I boot from the partition, it will wipe everything and bring it back the way I had it when I made the .wim image. Right now the only point in my Autounattend.xml file is to tell it what partition to install to so I only have to worry about partitioning everything once. Which is why my biggest concern is why the Autounattend.xml file isn't working when I boot from a partition, yet it does when I boot from a flash drive.

Installing Windows 7 is easy to begin with, but using a SysPrepped backup image is as simple as applying an image and would likely take even less time that reinstalling - attended or not.

Here's what I ended up doing:

I customized WinPE (with the help of this article) by adding the following line in the Startnet.cmd file:

I closed the WinPE image and copied it to a folder on the second partition on the hard drive. Then I pointed the bootloader to the boot.wim file in WinPE. This way, WinPE will execute the setup.exe and now Autounattend.xml will work.

Now I'm just trying to figure out how to keep it from adding an extra "Windows 7" boot entry every time I install from this partition.