I need to change background color

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Hi all,
as in object I need to set all my 350 desktops background colors to black.
Company policy...
Now I discover that GP do not do that and I need to create an ADM file and
add it to a GP.
I found an ADM that should change the background color but it do not work.
I know it is a ... Company Policy, but that is.

Any other works in similar company and solved this "problem"???
I really dislike to change 350 pc one by one.

Thanks in advance
--
Arnold


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