This example kills all but the most recent CMD.EXE on the local "." computer.

Test it by starting a few console sessions, then run the script - from the most recent console of course!

Code:
Break ON
$=SetOption("Explicit","ON")
$=SetOption("WrapAtEOL","ON")
 
Dim $sComputer,$sExe
Dim $oWMI,$cProcesses,$oProcess,$sProcessDate,$oProcessHold
 
$sComputer="."
$sExe="CMD.EXE"
 
$oWMI=GetObject("winmgmts:{impersonationLevel=impersonate}!\\"+$sComputer+'\root\cimv2')
If @ERROR or VarType($oWMI)<>9 "Cannot create WMI object: ["+@ERROR+"] "+@SERROR+@CRLF Exit @ERROR EndIf
$cProcesses=$oWMI.ExecQuery("select * from Win32_Process where Name=" +'"'+$sEXE+'"')
If @ERROR or VarType($cProcesses)<>9 "Cannot create process collection: ["+@ERROR+"] "+@SERROR+@CRLF Exit @ERROR EndIf
 
For Each $oProcess in $cProcesses
	If $sProcessDate=""
		$oProcessHold=$oProcess
		$sProcessDate=$oProcess.CreationDate
	Else
		If $oProcess.CreationDate > $sProcessDate
			"Killing "+$oProcessHold.ProcessID+" which started at "+$oProcessHold.CreationDate+@CRLF
			$oProcessHold=$oProcess
			$sProcessDate=$oProcess.CreationDate
        		$=$oProcessHold.Terminate
			If @ERROR "**ERROR**: Could not kill process ["+@ERROR+"] "+@SERROR+@CRLF EndIf
		Else
			"Killing "+$oProcess.ProcessID+" which started at "+$oProcess.CreationDate+@CRLF
        		$=$oProcess.Terminate
			If @ERROR "**ERROR**: Could not kill process ["+@ERROR+"] "+@SERROR+@CRLF EndIf
		EndIf
	EndIf
Next
 
"Will not kill process "+$oProcessHold.ProcessID+" which started at "+$oProcessHold.CreationDate+@CRLF
 
Exit 0