After you install Windows 8, you may find the CD/DVD drive is not recognized.
1. Run Command Prompt as an Administrator. Type cmd in Windows 8 Metro UI and press cltr+shift+enter
2. Type following and say enter
reg.exe add "HKLM\System\CurrentControlSet\Services\atapi\Controller0" /f /v EnumDevice1 /t REG_DWORD /d 0x00000001
3. Reboot the system
4. Verify if the problem has been resolved.