## Q:\Test\2017\01\21\SO_41785413.ps1
$FileOut = ".\Computers.csv"
## Ping subnet
$Subnet = "192.168.xyz."
1..254|ForEach-Object{
    Start-Process -WindowStyle Hidden ping.exe -Argumentlist "-n 1 -l 0 -f -i 2 -w 1 -4 $SubNet$_"
}
$Computers =(arp.exe -a | Select-String "$SubNet.*dynam") -replace ' +',','|
  ConvertFrom-Csv -Header Computername,IPv4,MAC,x,Vendor|
                   Select Computername,IPv4,MAC

ForEach ($Computer in $Computers){
  nslookup $Computer.IPv4|Select-String -Pattern "^Name:\s+([^\.]+).*$"|
    ForEach-Object{
      $Computer.Computername = $_.Matches.Groups[1].Value
    }
}
$Computers
$Computers | Export-Csv $FileOut -NotypeInformation
#$Computers | Out-Gridview