The trouble is I have no idea what are registry like before the user is logged on for the first time, so maybe trying to modify HKCU during setupcomplete.cmd phase is pointless.

Maybe the theme settings are saved in more locations than just HKCU\Software\Microsoft\Windows\CurrentVersion\Themes, because after the system booted to desktop and I manually changed the registry and restarted, the theme didn't change either!

The trouble is I have no idea what are registry like before the user is logged on for the first time, so maybe trying to modify HKCU during setupcomplete.cmd phase is pointless.

Maybe the theme settings are saved in more locations than just HKCU\Software\Microsoft\Windows\CurrentVersion\Themes, because after the system booted to desktop and I manually changed the registry and restarted, the theme didn't change either!

I guess you need to change the registries in preinstall environment, so only I insisted you to mount the wim, load the registry hives and then make the necessary changes. Secondly the msstyle files are the files which contains png files of theme and metadata. You can find this file in the "%Windir%\resources\themes\Aero" and default name is "Aero.msstyle"

Ok, if you only want a default aero theme that too without wallpaper, just delete the wallpaper in the Aero folder and "%windir%\web\wallpaper" I think this would work for you.

Not really, sound scheme and some other minor things are tied to themes as well

I really am starting to think this is a design flaw of some sort, because I even copied the theme over to the reference installation, actived it, generalized and captured the image and it STILL DOES NOT WORK. Jeez.

What does InstallTheme do anyway? Or what's the difference from CurrentTheme?