Windows Server 2008 servers are rebooting in workgroup

Are there any errors logged in the event log on the windows 2008 server?
Was adprep run on the windows 2003 master DC to upgrade the schema to include windows 2008?
Not sure enabling a more detailed auditing policy to apply to this server will be of any use.
Why not let the computer account get created when the system is joined into the domain?

There are no errors shown in the event logs. Adprep was not run as we don't have 2008 dc's. We did try adding the server back to the domain and let the computer account get created, but without result.

The computer account does not automatically get removed when a computer is removed from the domain.
Were there recent patches applied to all windows 2008 servers?
May be someone who has run into a similar issue will address it, but it sounds strange.  Strange question perhaps, are the servers running UAC while they are being joined into the domain?  Maybe UAC is what forces the server out of the domain reverting to prior "pristine" state?

I did some further research on the issue. We are using Altiris for deployment and patch management. I removed the agents on one of the servers to test if it would keep running. In the meantime I started a search on internet and I found the following article:
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DS agents and Vista!!!
Whenever deploying Vista with DS and using the NS to deploy the AClient then PLEASE make sure NOT to install the regular AClient , but use only the DAgent.

What happend:
We created a vista image and our XML, we deployed with Altiris Deployment Server and everything went fine. We use a runonce command to install the latetst NS and DS agent the at the first logon and the a reboot after 30 seconds.
After the reboot the NS agent agent starts communicating with the NS Server and gets its sub agents like SWD, PM, App Met, etc...If yo use the standard task to deploy the AClient then an (old) Aclient agent will be installed in addition to the already installed DAgent after a while.

In our case this resulted in a reconfiguration of the PC into the workgroup "WORKGROUP" after a reboot.
The collection of this task should be altered to prevent this task to be run on a VISTA Pc, so just clone the standard Collection to be used and add the exclusion of All Windows VISTA computers.
Running a Configuration job didn't fix the problem (I guess both agents wants to take control)

In any case, prevent the presence of 2 DS agents (Dagent and Aclient) on a VISTA...believe me.
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The same problem occurs on Windows 2008 server. We will do some further testing and upgrade Altiris to the latest versions. I will post the results before I close the item.

OK