How LoginStudio change the login screen?

Looks wise or technically wise?

Looks wise changes to skin you choose to use.

Technically wise, it is safe to use, it does not hack your system.

Tech Wise. I do know it's safe to use. I was wondering how it did it.
I figure it must have some kind of code that runs as part of the logon screen to change it.
In which if so my questions would be:
1. How does it get Windows to load it's dll/ocx/whatever file to load with login screen?
2. How does that whatever file change the login screen?

Logon Studio leaves the C:\Windows\System32\logonui.exe alone and instead has Windows use logonuiX.exe as the logon.

When you change a logon with Logon Studio, it changes the logonuiX.exe which Windows will use as the logon. If you uninstall Logon Studio, Windows will revert back to using logonui.exe as the default logon.

I guess that makes since.
I wonder though what happens if you install a Service Pack with a new logonui.exe file and Windows uses logonuiX.exe that hasn't been updated?

There should be no problem because Windows will still use the .logonuiX.exe with Logon Studio installed and use the new logonui.exe if Logon Studio is uninstalled.

Ok. I was thinking along the lines of if a service pack change caused LogonStudio's loginuiX.exe to crash how would you login then.

I had LogonStudio installed and in use when I first installed SP2, never had a problem.

ctrl+alt+del twice

Ok.
Also I just looked and didn't see a LoginUIX.exe file so maybe that's not quite how it's done on Vista.

You'll have to use LogonStudio Vista for Vista, the XP one won't work. The Vista version only changes the wallpaper at this point.

Ok. I'm using LogonStudio Vista and it does change the logon screen wallpaper. I'm just wondering how it does it.
I looked with Process Monitor and it shows LoginUI.exe was running while locked and LoginUI.exe doesn't appear to be changed so LogonStudio must be doing something other then using a LoginUI.exe

@boss0190, rickalot: That sounds like how it could be done except that after setting the login wallpaper I can't find a LogonUIX.exe file in the system32 directory.

I think I'll see if I can just email Stardock directly and ask them.

Don't use login, but I would expect to find LogonUIX.exe in LoginStudio in my program files. That then takes over the running of login, instead of going to C:\Windows\System32\logonui.exe. Sure support will be happy to explain what happens.

I did check in Program Files and didn't find anything.
Thanks to all for the help so far. I would figure LoginStudio used a LoginUIX.exe for a while and then they figured out a better way to do it.
Also I just emailed support and got back an automated message that had at the bottom "NOTE: Our office will be CLOSED beginning Monday, December 24th, in observance of Christmas and New Years. We will resume regular office hours Wednesday, February 2nd."
I guess I won't be finding answer anytime soon. Not a big deal as I was just curious how it worked and can wait.

AFAIK on Vista it's modifying resource dlls, well only one at the moment (the one with the background).

The logon screen uses resources from 3 dlls:
- imageres.dll : contains the background image, the waiting animation and the startup sound
- authui.dll : contains all the UI elements and the UI scripts
- branding.dll : contains the vista logo and vista edition name

You can have a look here to get a little bit more related info.

BTW, emailing support to get technical info on the inner-workings of Stardock programs is not going to get you anywhere...

I was assuming you were using XP, didn't realize you were using Vista. My explanation was for XP...sorry.

No-one mentioned 'LogonStudio Vista'   

@Littleboy: It appears you are correct. I looked in system32 and the imageres.dll did change. I guess Stardock decided that patching that file wouldn't cause any problems.
@Boss0190: That's ok, I should have mentioned in my first post I was using the Vista version.

I can't find the branding.dll file. This one, I am most anxious to find. Does anyone know where to locate it? (Windows Vista Ultimate, btw)