Can this be done? Use ADSI logged in as a Local User to modify Domain User Attributes in AD

Scenario:

- Newly imaged PC not joined to the domain logged in as a Local Admin (Username = User1)

- Run a batch file to start a PowerShell Script as a Domain User (net use etc.. powershell.exe -excutionpolicy bypass -file c:local file copied as part of the image)

- PowerShell script 1:

        - sets up credentials and adds PC to domain

- asks for username of person PC is being built for and then adds to Adminsitrators and Remote Desktop Groups

This all works great.  What i am trying to do is automate the build process for our ConferenceRoom PC's.  The ConferenceRoom PC's all use a single Domain account called ConferenceRoom, but in order to log into a PC using ConferenceRoom, the PC name has to be added to the attribute "UserWorkstations".  I wrote the following code that gets the current list of PC's names listed in that attribute using ADSI and then adds the PC the code is run on.  

$PCUser = Read-Host 'PLEASE ENTER THE USERNAME OF THE PERSON YOU ARE BUILDING THE PC FOR'

    ## Add PC to ConferenceRoom ID Logon Allowed Logon Workstations
    If ($PCUser -eq "ConferenceRoom")
            {
             $LOsearcher = New-Object System.DirectoryServices.DirectorySearcher([ADSI]'') 
             $LOsearcher.Filter = "(&(objectClass=User)(samAccountName=$PCUser))" 
             $LOresult = $LOsearcher.FindOne() 
             $LOuser = [ADSI] $LOresult.path
             $LOuser.psbase.invokeSet("userWorkstations",$CN)
             $LOuser.setinfo() 
            }

This runs perfectly from both my PC, when I am logged on as myself on the domain and on the newly imaged test PC only when I am logged on to the domain.  

When run the PowerShell script above, logged in as User1, it fails at 

$LOresult = $LOsearcher.FindOne()

The error is Exception calling "FindOne" with "0" argument(s): "The specified domain either does not exist or it could not be contacted."

I have tried adding credentials to the script, but I continually get the error.  So I guess my questions are as follows:

1.  Can what I want to do be done?

2.  If yes, I assume I need the proper credentials, but I cannot figure out how to code it.  How would I add credentials to the code?

I always appreciate the help I get here.  Sooner or later, I am going to fully understand all of this.  

Matt 

Matt Dillon