Powershell change local administrator account password for all computers in the domain

Hi mates,
how many times you asked to yourself : how can I change all pcs local administrator password ?
I had the need to change it for all computers in one of my customer domain.
The password was compromised and the old Microsoft GPO was no longer working (a patch disabled it for security reasons - MS14-025: Vulnerability in Group Policy Preferences could ... - https://support.microsoft.com/en-us/kb/2962486).
So what to do ?

Exchange 2003 & mailbox queries.....no powershell

We needed to query AD from Exchange 2003. We know that this version is not fully "queriable" by powershell.
I'd to understand how to retrieve some important information. We had for example an archiving system that use the group membership to "understand" if your mailbox is "storable" or not.
I took the opportunity also to grab other useful info .....let's see
Why don't use AD query tool ?

So let's do some queries to understand the structure.