PowerShell: How to find and uninstall a MS Office Update - powershell

Question

I've been hunting for a clean way to uninstall an MSOffice security update on a large number of workstations. I've found some awkward solutions, but nothing as clean or general like using PowerShell and get-wmiobject with Win32_QuickFixEngineering and the .Uninstall method on the resulting object.
[Apparently, Win32_QuickFixEngineering only refers to Windows patches. See: http://social.technet.microsoft.com/Forums/en/winserverpowershell/thread/93cc0731-5a99-4698-b1d4-8476b3140aa3 ]
Question 1: Is there no way to use get-wmiobject to find MSOffice updates? There are so many classes and namespaces, I have to wonder.
This particualar Office update (KB978382) can be found in the registry here (for Office Ultimate):
HKLM\Software\Microsoft\Windows\CurrentVersion\Uninstall\{91120000-002E-0000-0000-0000000FF1CE}_ULTIMATER_{6DE3DABF-0203-426B-B330-7287D1003E86}
which kindly shows the uninstall command of:
msiexec /package {91120000-002E-0000-0000-0000000FF1CE} /uninstall {6DE3DABF-0203-426B-B330-7287D1003E86}
and the last GUID seems constant between different versions of Office.
I've also found the update like this:
$wu = new-object -com "Microsoft.Update.Searcher"
$wu.QueryHistory(0,$wu.GetTotalHistoryCount()) | where {$_.Title -match "KB978382"}
I like this search because it doesn't require any poking around in the registry, but:
Question 2: If I've found it like this, what can I do with the found information to facilitate the Uninstall?
Thanks

Answer 1

Expanding on your second approach (using Microsoft.Update.Searcher), this solution should allow you to search for an update by Title then uninstall it:
$TitlePattern = 'KB978382'
$Session = New-Object -ComObject Microsoft.Update.Session
$Collection = New-Object -ComObject Microsoft.Update.UpdateColl
$Installer = $Session.CreateUpdateInstaller()
$Searcher = $Session.CreateUpdateSearcher()
$Searcher.QueryHistory(0, $Searcher.GetTotalHistoryCount()) |
Where-Object { $_.Title -match $TitlePattern } |
ForEach-Object {
Write-Verbose "Found update history entry $($_.Title)"
$SearchResult = $Searcher.Search("UpdateID='$($_.UpdateIdentity.UpdateID)' and RevisionNumber=$($_.UpdateIdentity.RevisionNumber)")
Write-Verbose "Found $($SearchResult.Updates.Count) update entries"
if ($SearchResult.Updates.Count -gt 0) {
$Installer.Updates = $SearchResult.Updates
$Installer.Uninstall()
$Installer | Select-Object -Property ResultCode, RebootRequired, Exception
# result codes: http://technet.microsoft.com/en-us/library/cc720442(WS.10).aspx
}
}