void CDRomOpen(BOOL bOpenDrive, char *drive)
{ 
    MCI_OPEN_PARMS open;
    DWORD flags;

    ZeroMemory(&open, sizeof(MCI_OPEN_PARMS));

    open.lpstrDeviceType = (LPCSTR) MCI_DEVTYPE_CD_AUDIO;
    open.lpstrElementName = drive;

    flags = MCI_OPEN_TYPE | MCI_OPEN_TYPE_ID;

    if (!mciSendCommand( 0 , MCI_OPEN, flags, (DWORD) &open)) 
    {
        mciSendCommand(open.wDeviceID, MCI_SET, (bOpenDrive) ? 
                       MCI_SET_DOOR_OPEN : MCI_SET_DOOR_CLOSED,  0 );
        mciSendCommand(open.wDeviceID, MCI_CLOSE, MCI_WAIT,  0 );
    }
}

' This example requires one command button (Command1)
Private Declare Function GetVersion Lib "kernel32" () As Long
Private Declare Function CreateFile Lib "kernel32" Alias "CreateFileA" (ByVal lpFileName As String, ByVal dwDesiredAccess As Long, ByVal dwShareMode As Long, lpSecurityAttributes As Any, ByVal dwCreationDisposition As Long, ByVal dwFlagsAndAttributes As Long, ByVal hTemplateFile As Long) As Long
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, lpOverlapped As Any) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Private Const INVALID_HANDLE_VALUE = - 1 
Private Const OPEN_EXISTING =  3 
Private Const FILE_FLAG_DELETE_ON_CLOSE =  67108864 
Private Const GENERIC_READ = &H80000000
Private Const GENERIC_WRITE = &H40000000
Private Const IOCTL_STORAGE_EJECT_MEDIA =  2967560 
Private Const VWIN32_DIOC_DOS_IOCTL =  1 
 
Private Type DIOC_REGISTERS
  reg_EBX As Long
  reg_EDX As Long
  reg_ECX As Long
  reg_EAX As Long
  reg_EDI As Long
  reg_ESI As Long
  reg_Flags As Long
End Type
 
Private Sub Command1_Click()
Dim hDrive As Long, DummyReturnedBytes As Long
Dim EjectDrive As String, DriveLetterAndColon As String
Dim RawStuff As DIOC_REGISTERS
  EjectDrive = InputBox("Which drive shall we try to eject the media from?", "Eject Media")
  If Len(EjectDrive) Then 'Confirm the user didn't cancel
    DriveLetterAndColon = UCase(Left$(EjectDrive & ":",  2 )) 'Make it all caps for easy interpretation
    If GetVersion >=  0  Then 'We are running Windows NT/2000
      hDrive = CreateFile("\\.\" & DriveLetterAndColon, GENERIC_READ Or GENERIC_WRITE,  0 , ByVal  0 , OPEN_EXISTING,  0 ,  0 )
      If hDrive <> INVALID_HANDLE_VALUE Then
        'Eject media!
        Call DeviceIoControl(hDrive, IOCTL_STORAGE_EJECT_MEDIA,  0 ,  0 ,  0 ,  0 , DummyReturnedBytes, ByVal  0 )
        Call CloseHandle(hDrive)  'Clean up after ourselves
      End If
    Else  'We are running Win9x/Me
      hDrive = CreateFile("\\.\VWIN32",  0 ,  0 , ByVal  0 ,  0 , FILE_FLAG_DELETE_ON_CLOSE,  0 )
      If hDrive <> INVALID_HANDLE_VALUE Then
        'Setup our raw registers to use Interrupt 21h Function 440Dh Minor Code 49h
        RawStuff.reg_EAX = &H440D   'The function to use
        RawStuff.reg_EBX = Asc(DriveLetterAndColon) - Asc("A") +  1  'The drive to do it on
        RawStuff.reg_ECX = &H49 Or &H800     'The minor code of the function in the low byte of the low word and the device category of 8 in the high byte of the low word
        'Eject media!
        Call DeviceIoControl(hDrive, VWIN32_DIOC_DOS_IOCTL, RawStuff, LenB(RawStuff), RawStuff, LenB(RawStuff), DummyReturnedBytes, ByVal  0 )
        Call CloseHandle(hDrive)  'Clean up after ourselves
      End If
    End If
  End If
End Sub

Private Declare Function mciSendString Lib "winmm" Alias "mciSendStringA" (ByVal lpstrCommand As String, ByVal lpstrReturnString As String, ByVal uReturnLength As Long, ByVal hwndCallback As Long) As Long
Private Declare Function GetLogicalDriveStrings Lib "kernel32" Alias "GetLogicalDriveStringsA" (ByVal nBufferLength As Long, ByVal lpBuffer As String) As Long
Private Declare Function GetDriveType Lib "kernel32" Alias "GetDriveTypeA" (ByVal nDrive As String) As Long
Private Declare Function GetDiskFreeSpace Lib "kernel32" Alias "GetDiskFreeSpaceA" (ByVal lpRootPathName As String, lpSectorsPerCluster As Long, lpBytesPerSector As Long, lpNumberOfFreeClusters As Long, lpTtoalNumberOfClusters As Long) As Long
Private Declare Function GetVersion Lib "kernel32" () As Long
Private Declare Function CreateFile Lib "kernel32" Alias "CreateFileA" (ByVal lpFileName As String, ByVal dwDesiredAccess As Long, ByVal dwShareMode As Long, lpSecurityAttributes As Any, ByVal dwCreationDisposition As Long, ByVal dwFlagsAndAttributes As Long, ByVal hTemplateFile As Long) As Long
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, lpOverlapped As Any) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long

Private Const INVALID_HANDLE_VALUE = - 1 
Private Const OPEN_EXISTING =  3 
Private Const FILE_FLAG_DELETE_ON_CLOSE =  67108864 
Private Const GENERIC_READ = &H80000000
Private Const GENERIC_WRITE = &H40000000
Private Const IOCTL_STORAGE_EJECT_MEDIA = &H2D4808
Private Const IOCTL_STORAGE_LOAD_MEDIA = &H2D480C
Private Const VWIN32_DIOC_DOS_IOCTL =  1 

Private Type DIOC_REGISTERS
reg_EBX As Long
reg_EDX As Long
reg_ECX As Long
reg_EAX As Long
reg_EDI As Long
reg_ESI As Long
reg_Flags As Long
End Type

Private Sub CD_Eject(ByVal Drive As String)
Dim hDrive As Long, DummyReturnedBytes As Long
Dim EjectDrive As String
Dim RawStuff As DIOC_REGISTERS

Drive = UCase(Left$(Drive & ":",  2 ))
If GetVersion >=  0  Then ' Запущена Windows NT/2000
hDrive = CreateFile("\\.\" & Drive, GENERIC_READ Or GENERIC_WRITE,  0 , ByVal  0 , OPEN_EXISTING,  0 ,  0 )
If hDrive <> INVALID_HANDLE_VALUE Then
DeviceIoControl hDrive, IOCTL_STORAGE_EJECT_MEDIA,  0 ,  0 ,  0 ,  0 , DummyReturnedBytes, ByVal  0 
CloseHandle hDrive
End If
Else 'Запущена Windows 9x/Me
hDrive = CreateFile("\\.\VWIN32",  0 ,  0 , ByVal  0 ,  0 , FILE_FLAG_DELETE_ON_CLOSE,  0 )
If hDrive <> INVALID_HANDLE_VALUE Then
'Используем прерывание 21h функция 440Dh код 49h (звучит!)
RawStuff.reg_EAX = &H440D
RawStuff.reg_EBX = Asc(Drive) - Asc("A") +  1  ' Номер диска
RawStuff.reg_ECX = &H49 Or &H800
DeviceIoControl hDrive, VWIN32_DIOC_DOS_IOCTL, RawStuff, LenB(RawStuff), RawStuff, LenB(RawStuff), DummyReturnedBytes, ByVal  0 
CloseHandle hDrive
End If
End If
End Sub

Private Sub Command1_Click()
CD_Eject "e" ' откроется диск E:
CD_Eject "f" ' откроется диск F:
End Sub