Option Explicit
Const ForReading = 1
Const ForWriting = 2
Dim objFSO,objFile,strText,strNewText,objRegEx
Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objFile = objFSO.OpenTextFile("C:\Users\newtons\Desktop\Text.txt",ForReading)
strText = objFile.ReadAll
objFile.Close
Set objRegEx = CreateObject("VBScript.RegExp")
objRegEx.Global = True
objRegEx.IgnoreCase = True
objRegEx.Pattern = "jim"
strNewText = objRegEx.Replace(strText,"James")
Set objFile = objFSO.OpenTextFile("C:\Users\newtons\Desktop\Text.txt",ForWriting)
objFile.WriteLine strNewText
objFile.Close
set objFSO = Nothing
set objFile = Nothing