Tenha paciência comigo enquanto estou fazendo isso da memória, mas isso deve funcionar:
$objWord = New-Object -comobject Word.Application
$objWord.Visible = $false
$list = Get-ChildItem "c:\users\stefan\test\*.*" -Include *.doc*
foreach($item in $list){
$objDoc = $objWord.Documents.Open($item.FullName,$true)
$objDoc.TrackRevisions = $true
$objDoc.ShowRevisions = $true
$objSelection = $objWord.Selection
$wdFindContinue = 1
$FindText = "Sara"
$MatchCase = $False
$MatchWholeWord = $true
$MatchWildcards = $False
$MatchSoundsLike = $False
$MatchAllWordForms = $False
$Forward = $True
$Wrap = $wdFindContinue
$Format = $False
$wdReplaceNone = 0
$ReplaceWith = "AJMOO"
$wdFindContinue = 1
$ReplaceAll = 2
$a = $objSelection.Find.Execute($FindText,$MatchCase,$MatchWholeWord, '
$MatchWildcards,$MatchSoundsLike,$MatchAllWordForms,$Forward,'
$Wrap,$Format,$ReplaceWith,$ReplaceAll)
$objDoc.Save()
$objDoc.Close()
}
$objWord.Quit()