Determine if product key is used on multiple computers

Question

I'm the sole programmer at company. Not only that, I'm the sole person who's remotely computer literate above the "I can check my email". As such, I've been asked to go to all the machines, and determine if any of the computers have duplicate install keys (the theory is the guy before me just didn't care and randomly used whatever key he pulled). Is there a way to determine this without installing any additional software?

Answer 1

Try and download Nirsoft's Produkey software. Install on USB key. Walk around, run it and send output to a file on the key. Doesn't require full installation - runs standalone. Shows OS key and Office key. May show other keys as well.

Answer 2

With Nirsoft's Produkey, you can retrieve all keys from computers on the network if you have local administrator rights on each or domain administrator rights with the command line flags /remoteall or /remotealldomain domain.com

http://www.nirsoft.net/utils/product_cd_key_viewer.html

Answer 3

Summary

The idea is to use PowerShell to query the license keys of list of PC names (input.csv).

The script will also check for duplicate keys and write the PC-Name, its corresponding license key and the duplicate check result to a new CSV (output.csv).

How to use

1. Create a CSV list as input. Write just one PC name per line. Save it as Input.csv
   In my example I query my own PC four times.
   

2. Download two PowerShell scripts to the same location as your input CSV

   Get-ProductKey.ps1 contains a single function to get product keys of local and remote systems and can be downloaded from Microsoft's script center.

   Write-ProductKeyList.ps1 will use the input CSV and the function script to write a new output CSV containing the results. Download it from Github or use the code below.

   . .\Get-ProductKey.ps1
   $InputCSV = import-csv .\Input.csv -Header Name
   $OutputCSV = @()  
   $Keys =@()
   
   foreach ($PC in $InputCSV)  
   {   
       $objResult = Get-ProductKey -Computername $PC.name                    
       $checkResult = $Keys -contains $objResult.ProductKey      
       $Keys += $objResult.ProductKey             
       $objResult | Add-Member -type NoteProperty -name Duplicate -value $checkResult          
       $OutputCSV = $OutputCSV + $objResult        
   }         
   $OutputCSV | Select-object Computername,OSDescription,ProductKey,Duplicate | export-csv -path .\Output.csv -noType
   

3. If you have all three files with the exact names at the same location, you're ready to go.
   Run the Write-ProductKeyList.ps1 script via right-click and Run with Powershell

Result (output.csv)

You will get a CSV file at the same location which you can open with Excel. The first occurrence of any license key will be marked with False, meaning there is yet no duplicate. Of course, all further (duplicate) keys will be marked as True meaning "Yes, this key was already used somewhere"

Preliminaries

• remote Windows machines must be reachable via network (obviously)
• "Remote Registry" service must be running on every remote machine (by default its on)