Private Sub CopyFileBlockSample()
    Const strFn = "CopyFileBlockSample"

    Dim strInFile As String
    strInFile = CombinePathAndFile(GetWindowsDirectory, "WIN.INI")
    strInFile = InputBox("Input file: ({Esc} cancels.)", strFn, strInFile)
    If Len(strInFile) = 0 Then Exit Sub

    Dim strOutFile As String
    strOutFile = GetTempFileName(Null, strFn)
    strOutFile = InputBox("Output file: (FILE WILL BE OVERWRITTEN; {Esc} cancels.)", strFn, strOutFile)
    If Len(strOutFile) = 0 Then Exit Sub

    Dim strStartByte As String
    strStartByte = InputBox("Start copying from byte: (Blank means start at beginning of file.)", strFn, "1024")

    Dim strCopyBytes As String
    strCopyBytes = InputBox("Copy number of bytes: (Blank means copy to end of file.)", strFn, "512")

    MsgBox "Return = " & CopyFileBlock(strInFile, strOutFile, strStartByte, strCopyBytes) & " (True means success; False means failure.)", vbInformation, strFn
End Sub