Vista Registry VirtualStore

My application installer (InnoSetup) creates a registry key called "auto" at "HKEY_LOCAL_MACHINE\SOFTWARE\Morpheus Software\Morpheus Photo Morpher" containing the activation code which the user enters during setup. When the program first runs, it sees this key, attempts to activate the software, then tries to create a key called "registration" in the very same location. The reason for this, is so that multiple users can have the software usable on one machine. All other registry access and settings is in HKEY_CURRENT_USER only.

This works fine on all windows through XP, and for nearly all of my users on Vista, but recently a few Vista users were having trouble with the software not staying activated for them. It turns out that the program is writing the "registration" key to "HKEY_CURRENT_USER\Software\Classes\VirtualStore\MACHINE\SOFTWARE\Morpheus Software\Morpheus Photo Morpher" but then trying to read the very same key from "HKEY_LOCAL_MACHINE\SOFTWARE\Morpheus Software\Morpheus Photo Morpher" where it doesn't exist.

What is the reason for this nonsense, and how can I have the user work around it, or program around this? I can't seem to find much information from Google other than the fact that Vista DOES do this. My installer has no trouble writing to the real location, and my program can read the "auto" key from the real location, but it can't seem to write back to the very same location.

My app is not exactly legacy, and the user IS running as an administrator, I verified that the InnoSetup installer ran correctly for them with the same user logged in, and it did not prompt for a different username/password to run. My InnoSetup configuration requires Admin privileges to run, so it shouldn't even install if that is not present. It was clearly able to create C:\Program Files\Morpheus Photo Morpher and write to that location, as well as HKLM in the registry from the installer.  But then my application, from the same user account, can't write to HKLM for some reason still.

Should the only conclusion be that the user is wrong, and they are simply not running as an Administrator?
The only test I have in the program code to prevent the user from activating as a non-admin account was to check if I can open the "registration" key for writing or not (which works on 2000/XP to tell Admin from non-Admin).

Ok, can you point me towards the API functions I need to use to elevate admin to real-admin and a better way to test if the current user is actually an admin to begin with?

What I still don't really understand though, is when the key is created at "HKEY_CURRENT_USER\Software\Classes\VirtualStore\MACHINE\SOFTWARE\Morpheus Software\Morpheus Photo Morpher" because of a write to "HKEY_LOCAL_MACHINE\SOFTWARE\Morpheus Software\Morpheus Photo Morpher", why does a read from "HKEY_LOCAL_MACHINE\SOFTWARE\Morpheus Software\Morpheus Photo Morpher" for the same key then fail? Shouldn't the READ be virtualized too?

So the entire app must run as elevated-admin, not just the dialog where registration happens then? 

A separate app or COM object for a couple-line popup dialog that does the registration simply isn't worth it. "highestAvailable" it is then.

Is there an API to check what level of permissions the applications is actually running with, since before I only checked if the key I wanted in HKLM was writable, and if that failed, greyed out the text box and put up a message stating that you must be administrator to activate the software. Now with Vista, that key will always be writable, even if it is virtualized.

Ark42 wrote: A separate app or COM object for a couple-line popup dialog that does the registration simply isn't worth it. "highestAvailable" it is then.Is there an API to check what level of permissions the applications is actually running with, since before I only checked if the key I wanted in HKLM was writable, and if that failed, greyed out the text box and put up a message stating that you must be administrator to activate the software. Now with Vista, that key will always be writable, even if it is virtualized.

If you are using a manifest, Vista doesn't virtualize registry and file access. You can check the virtualization status with Task Manager, there is a special column for virtualization.