When you have installed Operating system

1) Just copy the code below & save it as .vbs extension
(e.g operating.vbs) in notepad .

2)Now double-click on this & know your oparting sytem installed
 date and Time.

' © 2006 Ramesh Srinivasan.<br />'Returns the Operating System installation date.<br />strComputer = "."<br />Set dtmInstallDate = CreateObject( _ <br />"WbemScripting.SWbemDateTime")<br />Set objWMIService = GetObject("winmgmts:" _<br />& "{impersonationLevel=impersonate}!\\" _<br />& strComputer & "\root\cimv2")<br />Set colOperatingSystems = objWMIService.ExecQuery _ <br />("Select * from Win32_OperatingSystem")<br />For Each objOperatingSystem in colOperatingSystems<br />MsgBox "Install Date: " & getmydat (objOperatingSystem.InstallDate)<br />Next <br /><br />Function getmydat(wmitime)<br />dtmInstallDate.Value = wmitime<br />getmydat = dtmInstallDate.GetVarDate<br />End function<br /><br />