Windows 7 - Block Wallpaper Change BUT allow Selected Slideshow Wallpapers

Question

System: Windows 7 Pro with SP2

Please can you help me find a solution to Allow Wallpaper Slideshow using a preselected folder BUT block anyone from changing the wallpaper.

The issue I am coming up with is the due to the slideshow option as most of the solutions allow for this but crucially only one wallpaper is ever displayed.

I appreciate anyone's thoughts or opinions and below is the list of attempted solutions that have not worked for what I am looking for:

Attempt 1: Group Policy Editor

Type gpedit.msc and press OK to open the Local Group Policy Editor.
Navigate to User Configuration > Administrative Templates > Control Panel > Personalization.
Double-click the Prevent changing desktop background option.
Selected Enabled option

RESULT: Removes access to change wallpaper BUT ALSO blocks the wallpaper slideshow - the wallpaper just remains on the wallpaper it was on right before this solution was enabled.

Attempt 2: Registry Editor

Open the Registry Editor.
Navigate to HKEY_CURRENT_USER > Software > Microsoft > Windows > CurrentVersion > Policies.
Right-click on the Policies key (folder) and select New > Key.
Name this key as ActiveDesktop and then press Enter.
Click on the ActiveDesktop key. Add and select New > DWORD (32-bit) Value.
Name the value as NoChangingWallPaper and then press Enter. 
NoChangingWallPaper value and set its Value data to 1. Click OK

RESULT: SAME AT ATTEMPT 1 - ie Removes access to change wallpaper BUT ALSO blocks the wallpaper slideshow - the wallpaper just remains on the wallpaper it was on right before this solution was enabled.

ATTEMPT 3: Group Policy Editor v2

Type gpedit.msc and press OK to open the Local Group Policy Editor.
Navigate to User Configuration > Administrative Templates > Desktop > Desktop.
Double-click the Desktop Wallpaper option.
In the next window, select the Enabled option

RESULT: It forces you to select just one wallpaper - not a series of wallpapers therefore not what I need

Answer 1

Not sure why I got downvoted for my question and apologise if I did something wrong :(

But in the spirit of these forums despite my downvote I thought I would post my answer so at least it could help someone in the future either on these forums or if they ever search and find it through Google etc.

Step 1: Set the Desktop Background to the slideshow settings you want (ie the folder where the images are stored, the timing frequency, shuffle etc)

Step 2: Go to Theme and now save these settings as a new Theme so it becomes a theme you can select

Step 3: Now this your new theme set go to Local Policy Editor

Step 4: Within Local Policy Editor go to User Configuration > Administrative Templates > Control Panel > Personalization

Step 5: Enable the 'Prevent Changing Theme'

Step 6: After Step 5 enable 'Prevent changing desktop background'

This will prevent anyone from changing the desktop background settings but still allow the slideshow feature to work without getting stuck on one wallpaper.