Ok well when your laptop is POSTing, it will list any hard drives/optical drives that are present. I'm not familiar with that specific model and some machines may prompt you to hit a key such as tab to show more boot details. Anyway, do you see your DVD drive listed? If not watch for whatever hotkey will allow you to get into the bios/setup screens and it will definitely be listed in here if it is available.
If the drive is detected by your OS, it is possible that you have other drive letters using the drive letter your optical drive wants to use.
Get your computer to "Computer Management" which you can get to by right clicking on the "My Computer" icon and choosing "Manage"
Then click on "Disk Management"
Now you will see a listing of all storage volumes that windows recognizes, You may see the CD-ROM 0 but no drive letter, if this is the case, you can right click and manually choose another drive letter. Give that a try and let us know the outcome