I've got an old VBscript on my desktop that does file renaming. Doesn't do capitals but you could change it to use the UCase or LCase functions. Paste it into a file with a .vbs extension and play around.

Option Explicit

Dim fsoReader
Dim strDir
Dim strFrom
Dim strTo
Dim objFolder
Dim varFile
Dim strName
Dim lngCount

'Initialize
strDir = "F:\AudioBooks\Disk 4"
strFrom = " - Orphans - Disk 4 - "
strTo = "Orphans4 "
lngCount = 0

'Confirm values
strDir = InputBox("Enter folder", "Bulk rename", strDir)
strFrom = InputBox("Rename from", "Bulk rename", strFrom)
strTo = InputBox("Rename to", "Bulk rename", strTo)

Set fsoReader = CreateObject("Scripting.FileSystemObject")
Set objFolder = fsoReader.GetFolder(strDir)

'Get each file
For Each varFile in objFolder.Files
    'New name
    strName = CStr(varFile.Name)
    strName = Replace(strName, strFrom, strTo)

    If CStr(varFile.Name) <> strName Then
        varFile.Name = strName
        lngCount = lngCount + 1
    End If
Next

MsgBox "Done. " & lngCount & " files were renamed"