If you're in Windows go into Device Manager under Control Panel > System (will slightly vary from XP to Vista) and check whether there are any unrecognized devices with an exclamation point icon next to them. If there are you can try searching for drivers through Windows Update. If your drive is listed under DVD/CD-ROM drives as normal you can try uninstalling the current drivers and resetting your machine, then allow Windows to install the drivers on newly recognized hardware.