Windows 7: Computer uses classic theme after update

I did run into an annoying thing, by mistake was that European browser selection "upgrade" installed into a PC running Windows 7 32 pro. After this, the computer uses the classic theme as default instead of Aero and I can't figure out how to force the PC into using Aero as default once more.

I have tried the following tricks:

-force the PC to use Aero as default through the local policy of the PC
-Pick out all parts of the registry on a working PC containing refereences to aero.theme and patch them into the problematic PC

If I manually switch to use the aero theme, it works nicely for that user, but as soon as another user logs on, it reverts to classic.

Apparently there are some registry settings that I haven't been able to find.

Any tips ? I don't want to throw a new image into that particular PC.

One of these should help:

Theme - Specify Default Theme to Load for New Users
configure same theme for all users
how to change the desktop theme for all users
How to customize the default local user profile when you prepare an image of Windows XP or Windows Server 2003

Patching the registry is a sure way to mess up Windows 7. I would System Restore to before you did this or look for problems down the line.

If this doesn't help then Restore to before you did the Browser upgrade - what was this exactly?

Rightclick the desktop>Personalize to choose an Aero Theme.

If that doesn't work run the Aero troubleshooter by typing Aero into Start Search box.

Well,

"If this doesn't help then Restore to before you did the Browser upgrade - what was this exactly?"

The browser selection "upgrade" is something that Microsoft had to give to the European Comission to prove that they does not stiffle free competition, when installed it removes the shortcuts to IE and "gives" you the "opportunity" to choose another browser from several different candidates ....

AFter this one was accidentally installed in the PC, my problems started.

To patch the registry is no problem, provided that you know what you are doing, well, otherwise

Theme - Specify Default Theme to Load for New Users - The first thing I tried to do. Won't work. Classic theme still loaded.

configure same theme for all users - Haven't tried this yet, will try. Did figure that it won't help, because it is the same thing as the previous step.

how to change the desktop theme for all users - Did that, didn't work. Nothing but an override to the local policy and my problem seems that there's somewhere a registry key missing or one that can't be identified by searching for themes.

Optimize Desktop Productivity with User Profiles - Here's something that might fix my problems, I'll have to try it.

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System restore isn't an option in this case.

Optimize Desktop Productivity with User Profiles - doesn't work anyy longer under Windows 7

And to create a new default profile is a lot work in Windows 7, you need a reference isntallation from which you extract an image of the profile you want etc etc, ie a registry hack seems to be my solution, I have ONLY to find the correct key to modify ....

Why is System Restore not an option? You should have restore points to choose from, and a Windows 7 backup image so if Windows 7 becomes corrupted or unbootable you can reimage the HD in 20 minutes.

System Restore
Backup Complete Computer - Create an Image Backup

Less work to push a new, clean image onto the PC .....

I'm looking into this more because I wan't to know what really has gone wrong.