....
        public static unsafe byte[] ReadSector(char drive, long startingsector, int numberofsectors)
        {
            IntPtr handle;
            byte[] buffer;
            int bytesread = 0;
            //create a handle to the device
            handle = CreateFile(
                "\\\\.\\" + drive + ":", FileAccess.Read, FileShare.ReadWrite, 0, FileMode.Open, 0, 0);
            if (handle == IntPtr.Zero)
                return null;
            //setting the pointer to point to the start of the sector to read
            SetFilePointer(handle, (startingsector * 512), 0, 0);
            //allocate buffer length in a managed context
            buffer = new byte[512 * numberofsectors];
            fixed (byte* p = buffer)
            {
                //attempt to read file contents into buffer
                if (!ReadFile(handle, p, 512 * numberofsectors, &bytesread, 0))
                {
                    CloseHandle(handle);
                    return null;    
               }
            }    
            CloseHandle(handle);
            return buffer;
        }
 ....