Yesterday I was working on a windows machine which was getting auto locked in a very short delay. If you are facing the same problem, you can write VBScript as follows:
Set WshShell = WScript.CreateObject("WScript.Shell")
Do
' Wait for ~1 minute
WScript.Sleep (60*1000)
WshShell.SendKeys "{NUMLOCK}"
i = 0
Loop Until (i=1)
Arpit Aggarwal Blog 