polls ad for computer objects that have not called home for a period of time, can either report or delete them.

stale ad computers

import-module activedirectory 

#finddomain or enter manually
#$domain = (Get-WmiObject Win32_ComputerSystem).Domain 
#domain = my.domain.com

#edit for number of days to go back
$DaysInactive = 90 
$time = (Get-Date).Adddays(-($DaysInactive))
 
# Get all AD computers with lastLogonTimestamp less than our time
Get-ADComputer -Filter {LastLogonTimeStamp -lt $time} -Properties LastLogonTimeStamp |
 
# Output hostname and lastLogonTimestamp into CSV
#select-object Name,@{Name="Stamp"; Expression={[DateTime]::FromFileTime($_.lastLogonTimestamp)}} | export-csv OLD_Computer.csv -notypeinformation

#delete AD objects
#remove-adcomputer