Rename all files in a folder with specific extension

strComputer = "."
Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")

Set FileList = objWMIService.ExecQuery _
    ("ASSOCIATORS OF {Win32_Directory.Name='C:\test'} Where " _
        & "ResultClass = CIM_DataFile")

For Each objFile In FileList
    strDate = Left(objFile.CreationDate, 8)
    strNewName = objFile.Drive & objFile.Path & _
       strDate & "." & "jpg"
    strNameCheck = Replace(strNewName, "\", "\\")

    i = 1
    Do While True
        Set colFiles = objWMIService.ExecQuery _
            ("Select * from Cim_Datafile Where Name = '" & strNameCheck & "'")
        If colFiles.Count = 0 Then
            errResult = objFile.Rename(strNewName)
            Exit Do
        Else
            i = i + 1
            strNewName = objFile.Drive & objFile.Path & _
                strDate & "" & i & "." & "jpg"
            strNameCheck = Replace(strNewName, "\", "\\")
        End If
    Loop
Next