VB Script does not change the value of the Environment variable TEMP

On Error Resume Next

Const wbemFlagReturnImmediately = &h10
Const wbemFlagForwardOnly = &h20

arrComputers = Array("SUNDAR-PC")

For Each strComputer In arrComputers
   WScript.Echo
   WScript.Echo "=========================================="
   WScript.Echo "Computer: " & strComputer
   WScript.Echo "=========================================="

   Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\CIMV2")
   Set colItems = objWMIService.ExecQuery("SELECT * FROM Win32_Environment where name = 'temp'", "WQL", _
                                          wbemFlagReturnImmediately + wbemFlagForwardOnly)

   For Each objItem In colItems
      WScript.Echo "Name: " & objItem.Name
      WScript.Echo "VariableValue: " & objItem.VariableValue
      strCurrentvalue = objItem.VariableValue
      WScript.Echo ""& strCurrentvalue
      objItem.VariableValue = "D:\Temp"
      WScript.Echo ""& objItem.VariableValue

   Next
Next


Function WMIDateStringToDate(dtmDate)
WScript.Echo dtm:
  WMIDateStringToDate = CDate(Mid(dtmDate, 5, 2) & "/" & _
  Mid(dtmDate, 7, 2) & "/" & Left(dtmDate, 4) _& " " & Mid (dtmDate, 9, 2) & ":" & Mid(dtmDate, 11, 2) & ":" & Mid(dtmDate,13, 2))
End Function

Hi Scripting Guys,

I am using the above script to change the value of environment variable TEMP to "D:\Temp.

When I run this script it shows the output "D:\Temp" but in the computer environment variable does not change. 

Please give the solution and why it is not changing the value.

Thanks in advance.

Sundar