Querying WMI-object for Services - How to port check for WMI and handle exceptions?

Hi

I've enabled Active Directory Gateway Management Services on our 2003 domain I can now Powershell AD objects :-)

First task of the day.

Aim: determine which services on our servers are authenticating with the Domain Admin password. Yeah, some people have been naughty.

I'm a PS noob, but some time ago obtained a BSc in Computer Science, so can understand the principles of coding, but don't do much these days.  Thus far I've spent my first few proper hours this afternoon with PS and cobbled together the following

# Load the MS Active Directory cmdlets
 Import-Module activedirectory

# Get a list of computers in the two Servers OU (must sort that out)
Get-ADcomputer -LDAPFilter "(name=*)" -SearchScope Subtree -SearchBase "ou=servers,ou=gloucester,DC=domain,dc=co,dc=uk" | foreach-object {$_.Name} | Out-File c:\scripts\servers.txt
Get-ADcomputer -LDAPFilter "(name=*)" -SearchScope Subtree -SearchBase "ou=servers,ou=machines,ou=gloucester,DC=domain,dc=co,dc=uk" | foreach-object {$_.Name} | Out-File c:\scripts\servers.txt -Append

# If output file already exists then remove it
If (Test-Path -Path "C:\scripts\audit.txt") {Remove-Item "C:\scripts\audit.txt"}

$compArray = get-content C:\Scripts\Servers.txt
foreach($strComputer in $compArray)
{
write-output "Checking $strComputer for domain\Administrator" | Out-File "C:\scripts\audit.txt" -Append
Get-WMIObject Win32_Service -ComputerName $strComputer | Where-Object {$_.StartName -eq 'domain\Administrator'} | Format-List Name, StartName | Out-File "C:\scripts\audit.txt" -Append
write-output "Checking $strComputer for Administrator@domain.co.uk" | Out-File "C:\scripts\audit.txt" -Append
Get-WMIObject Win32_Service -ComputerName $strComputer | Where-Object {$_.StartName -eq 'Administrator@domain.co.uk'} | Format-List Name, StartName | Out-File "C:\scripts\audit.txt" -Append
}

That works for what can be contacted. However I need to handle this:

Get-WmiObject : The RPC server is unavailable. (Exception from HRESULT: 0x80070
BA)
t C:\scripts\wipservices.ps1:17 char:14
 Get-WMIObject <<<<  Win32_Service -ComputerName $strComputer | Where-Object {
_.StartName -eq 'Administrator@impello.co..uk'} | Format-List Name, StartName
 Out-File "C:\scripts\audit.txt" -Append
   + CategoryInfo          : InvalidOperation: (:) [Get-WmiObject], COMExcept
  ion
   + FullyQualifiedErrorId : GetWMICOMException,Microsoft.PowerShell.Commands
  .GetWmiObjectCommand