Your CD/DVD drive isn’t appearing on “Computer”, this sometimes happens when you have just installed or uninstalled a program also may be when you updated Windows Vista. Here are a couple solutions that should help you solve this problem.
To roll back these changes you can try restoring the system, To do this:
Click Start or Vista icon then type “System Restore” in the “Start Search” field.
Press Enter then click on open to give permission to open System Restore
On “Recommended Restore” select a Restore point.
Then click on “Next” to proceed
Click on “Finish”
This will restore your system to a previous date when the changes has been made.
Restart the computer and try to check if you can see your drive.
You can also try to remove and to reinstall the drive’s drivers
Right Click on “Computer” from the Start menu,
On the Task options at your left click on “Device Manager”
Expand “DVD/CD-Rom drives”
Right click on it, click “Uninstall”
Then Press “OK” to confirm
Restart the computer, which will automatically install the drivers!