Am looking for somebody to create me a script (Windows, bat or
otherwise), that will run automatically and update a value in an
existing key within the Windows Registry. Exact key location will be
provided.

================
Use batch file:
================

1.create an text file for the registry value you want to add,, like:

c:\test.reg
----------------------------------------------
Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
"WinVNC"="\"C:\\Program Files\\UltraVNC\\WinVNC.exe\" -Servicehelper"

2.write an batch file

test.bat
----------------------------------------------
regedit /s c:\test.reg

If you don't know how the syntax about test.reg, you can make your
registry entry with regedit then export the section to .reg file.


====================
Using windows script
====================

create a text file name c:\test.vbs
-----------------------------------
Set WSHShell = CreateObject("WScript.Shell")
WSHShell.RegWrite "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\Lee",
"c:\windows\notepad.exe"

run this test file:
wscript c:\test.vbs

for more information aboyt windows script host, please visit:
http://msdn.microsoft.com/archive/default.asp?url=/archive/en-us/wsh/htm/wsMthRegWrite.asp