Const ForReading = 1
Const ForWriting = 2

strFileName = Wscript.Arguments(0)
strOldText = Wscript.Arguments(1)
strNewText = Wscript.Arguments(2)

Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objFile = objFSO.OpenTextFile(strFileName, ForReading)

strText = objFile.ReadAll
objFile.Close
strNewText = Replace(strText, strOldText, strNewText)

Set objFile = objFSO.OpenTextFile(strFileName, ForWriting)
objFile.WriteLine strNewText
objFile.Close

@echo off
echo Const ForReading = 1 > replace.vbs
echo Const ForWriting = 2 >> replace.vbs

echo strFileName = Wscript.Arguments(0) >> replace.vbs
echo strOldText = Wscript.Arguments(1) >> replace.vbs
echo strNewText = Wscript.Arguments(2) >> replace.vbs

echo Set objFSO = CreateObject("Scripting.FileSystemObject") >> replace.vbs
echo Set objFile = objFSO.OpenTextFile(strFileName, ForReading) >> replace.vbs

echo strText = objFile.ReadAll >> replace.vbs
echo objFile.Close >> replace.vbs
echo strNewText = Replace(strText, strOldText, strNewText) >> replace.vbs

echo Set objFile = objFSO.OpenTextFile(strFileName, ForWriting) >> replace.vbs
echo objFile.WriteLine strNewText >> replace.vbs
echo objFile.Close >> replace.vbs

cscript replace.vbs "C:\Scripts\Text.txt" "Jim " "James ""

del replace.vbs