UINT GetDriveType(LPCTSTR lpRootPathName);

ManagementObjectSearcher objectSearcher = new ManagementObjectSearcher("SELECT * FROM Win32_CDROMDrive");
foreach(ManagementObject cdrom in objectSearcher.Get())
    Console.WriteLine(cdrom.GetPropertyValue("Drive"));

    /// <summary>
    /// Describes available types for local drives
    /// </summary>
    public enum DriveType : int
    {
        /// <summary>
        /// The drive type cannot be determined
        /// </summary>
        Unknown = 0,
        
        /// <summary>
        /// The root path is invalid. For example, no volume is mounted at the path
        /// </summary>
        NotRootDir = 1,

        /// <summary>
        /// The disk can be removed from the drive.
        /// </summary>
        Removable = 2,

        /// <summary>
        /// The disk cannot be removed from the drive.
        /// </summary>
        Fixed = 3,

        /// <summary>
        /// The drive is a remote (network) drive.
        /// </summary>
        Remote = 4,

        /// <summary>
        /// The drive is a CD-ROM drive.
        /// </summary>
        CDROM = 5,

        /// <summary>
        /// The drive is a RAM disk.
        /// </summary>
        RamDisk = 6, 
    }

    /// <summary>
    /// Class for querying drives
    /// </summary>
    public class Drive
    {
        [DllImport("kernel32", CharSet = CharSet.Auto)]
        private extern static DriveType GetDriveType(string rootPath);

        /// <summary>
        /// Return array of all logical drives in system
        /// </summary>
        /// <returns>Array of strings, listing all logical drives in the local system</returns>
        public static string[] GetDrives()
        {
            return Directory.GetLogicalDrives();
        }

        /// <summary>
        /// Return array of logical drives in local system of one of the specified types
        /// </summary>
        /// <param name="driveTypes">Array of driveTypes that should be listed</param>
        /// <returns>Array of strings, listing logical drives of specified type(s)</returns>
        public static string[] GetDrives(DriveType[] driveTypes)
        {
            ArrayList drives = new ArrayList();
            string[] alldrives = Directory.GetLogicalDrives();
            foreach(string drive in alldrives)
            {
                DriveType dt = GetDriveType(drive);
                foreach(DriveType match in driveTypes)                
                    if (dt == match)
                    {
                        drives.Add(drive);
                        break;
                    }
            }
            return (string[])drives.ToArray(typeof(string));
        }

        /// <summary>
        /// Return array of logical drives in local system of the specified type
        /// </summary>
        /// <param name="driveType">Type of drives that should be listed</param>
        /// <returns>Array of strings, listing logical drives of specified type</returns>
        public static string[] GetDrives(DriveType driveType)
        {
            ArrayList drives = new ArrayList();
            string[] alldrives = Directory.GetLogicalDrives();
            foreach(string drive in alldrives)
            {
                DriveType dt = GetDriveType(drive);
                if (dt == driveType)
                    drives.Add(drive);
            }
            return (string[])drives.ToArray(typeof(string));
        }
    }

_>ManagementObjectSearcher objectSearcher = new ManagementObjectSearcher("SELECT * FROM Win32_CDROMDrive");
_>foreach(ManagementObject cdrom in objectSearcher.Get())
_>    Console.WriteLine(cdrom.GetPropertyValue("Drive"));
_>

ManagementObjectSearcher cdSearcher = new ManagementObjectSearcher("SELECT * FROM Win32_CDROMDrive");
     foreach (ManagementObject cdRom in cdSearcher.Get())
              listBox1.Items.Add(cdRom["VolumeSerialNumber"].ToString());