To access a hard drive's sector level, you need to use low level API.
Basically, the two functions you will need here will be something like that:
Private Function ReadHDBytes (ByVal ByteCount As Long, ByRef DataBytes () As Byte, ByRef ActuallyReadByte As Long) As Boolean
Dim RetVal As Long
RetVal = ReadFile (hDisk, DataBytes (0), ByteCount, ActuallyReadByte, 0)
ReadHDBytes = Not (RetVal = 0)
End Function
Private Function WriteHDBytes (ByVal ByteCount As Long, ByRef DataBytes () As Byte) As Boolean
Dim RetVal As Long
Dim BytesToWrite As Long
Dim BytesWritten As Long
RetVal = WriteFile (hDisk, DataBytes (0), ByteCount, BytesWritten, 0)
WriteHDBytes = Not (RetVal = 0)
End Function
Before being able to call these functions, you must add the following lines of code in order to access Win32 API from VB.
Private Declare Function CreateFile Lib "kernel32" Alias "CreateFileA" (ByVal lpFileName As String, ByVal dwDesiredAccess As Long, ByVal dwShareMode As Long, lpSecurityAttributes As Long, ByVal dwCreationDisposition As Long, ByVal dwFlagsAndAttributes As Long, ByVal hTemplateFile As Long) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Private Declare Function ReadFile Lib "kernel32" (ByVal hFile As Long, lpBuffer As Any, ByVal nNumberOfBytesToRead As Long, lpNumberOfBytesRead As Long, ByVal lpOverlapped As Long) As Long
Private Declare Function WriteFile Lib "kernel32" (ByVal hFile As Long, lpBuffer As Any, ByVal nNumberOfBytesToWrite As Long, lpNumberOfBytesWritten As Long, ByVal lpOverlapped As Long) As Long
Private Declare Function SetFilePointer Lib "kernel32" (ByVal hFile As Long, ByVal lDistanceToMove As Long, lpDistanceToMoveHigh As Long, ByVal dwMoveMethod As Long) As Long
Private Const GENERIC_READ = & H80000000
Private Const GENERIC_WRITE = & H40000000
Private Const FILE_SHARE_READ = & H1
Private Const FILE_SHARE_WRITE = & H2
Private Const OPEN_EXISTING = 3
Private Const INVALID_HANDLE_VALUE = -1
Private Const FILE_BEGIN = 0
Private Const FILE_CURRENT = 1
Private Const FILE_END = 2
Private Const ERROR_SUCCESS = 0 &
Private Declare Function DeviceIoControl Lib "kernel32" (ByVal hDevice As Long, ByVal dwIoControlCode As Long, lpInBuffer As Any, ByVal nInBufferSize As Long, lpOutBuffer As Any, ByVal nOutBufferSize As Long, lpBytesReturned As Long, ByVal lpOverlapped As Long) As Long
Private Const IOCTL_DISK_GET_DRIVE_GEOMETRY As Long = & H70000
Private Const IOCTL_STORAGE_GET_MEDIA_TYPES_EX As Long = & H2D0C04
Private Const IOCTL_DISK_FORMAT_TRACKS As Long = & H7C018
Private Const FSCTL_LOCK_VOLUME As Long = & H90018
Private Const FSCTL_UNLOCK_VOLUME As Long = & H9001C
Private Const FSCTL_DISMOUNT_VOLUME As Long = & H90020
Private Const FSCTL_GET_VOLUME_BITMAP = & H9006F
Private Type LARGE_INTEGER
lowpart As Long
highpart As Long
End Type
Private Enum MEDIA_TYPE
Unknown
F5_1Pt2_512
F3_1Pt44_512
F3_2Pt88_512
F3_20Pt8_512
F3_720_512
F5_360_512
F5_320_512
F5_320_1024
F5_180_512
F5_160_512
RemovableMedia
FixedMedia
End Enum
Private Type DISK_GEOMETRY
Cylinders As LARGE_INTEGER
MediaType As MEDIA_TYPE
TracksPerCylinder As Long
SectorsPerTrack As Long
BytesPerSector As Long
End Type
Private hDisk As Long
Private lpGeometry As DISK_GEOMETRY
Private lBufferSize As Long
Of course, this is not a complete solution, but only to give you some directions to continue from here.