type

 TSector = array[0..511] of Byte;

var

 Boot: TSector;

begin

 ReadBoot(Drive, Boot);

//для 95, 98, Me

type

  TDiocRegisters = record

  EBX, EDX, ECX, EAX, EDI, ESI, Flags: LongWord end;

  TVWin32CtlCode = (ccNone, ccVWin32IntIoctl, ccVWin32Int25,

  ccVWin32Int26, ccVWin32Int13);

 function VWin32(CtlCode: TVWin32CtlCode;

  var Regs: TDiocRegisters): Boolean; // вспомогательная процедура

 var

  Device: THandle;

  Count: LongWord;

  begin

  Device := CreateFile('\.\VWIN32', 0, 0, nil, 0,

  FILE_FLAG_DELETE_ON_CLOSE, 0);

  if Device = INVALID_HANDLE_VALUE then

  raise Exception.Create(SysErrorMessage(GetLastError));

  try

  Result := DeviceIoControl(Device, Ord(CtlCode), @Regs,

  SizeOf(Regs), @Regs, SizeOf(Regs), Count, nil);

  finally

  CloseHandle(Device) end end;

//само чтение

procedure ReadBoot95(Drive: Char; var Boot: TSector);

  var

  Regs: TDiocRegisters;

  begin

  with Regs do begin

  EAX := Ord(UpCase(Drive)) - Ord('A');

  EBX := LongWord(@Boot);

  ECX := 1;

  EDX := 0 end;

  if not VWin32(ccVWin32Int25, Regs) then

  raise Exception.Create(SysErrorMessage(GetLastError)) end;

//для NT, 2000, XP попроще

type

  TSector = array[0..511] of Byte;

 procedure ReadBootNT(Drive: Char; var Boot: TSector);

  var

  BytesRead: Cardinal;

  H: THandle;

  begin

  H := CreateFile(PChar(Format('\.\%s:', [UpCase(Drive)])),

  GENERIC_READ, 0, nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);

  if H = INVALID_HANDLE_VALUE then

  raise Exception.Create(SysErrorMessage(GetLastError));

  try

  if not ReadFile(H, Boot, SizeOf(Boot), BytesRead, nil)then

  raise Exception.Create(SysErrorMessage(GetLastError));

  finally

  CloseHandle(H) end end;

// а юзать так

var

  Boot: TSector;

  begin

  case Win32Platform of

  VER_PLATFORM_WIN32_WINDOWS:

  ReadBoot95(Drive, Boot);

  VER_PLATFORM_WIN32_NT:

  ReadBootNT(Drive, Boot) end;