|Have you, or is it possible anyone else has|
- dropped this laptop ?
- spilled liquid in it ?
- ran into the drive's tray or otherwise subjected the optical drive to a physical jolt when the tray was ejected ?
If you or someone did any of those things, that's not covered by your warranty, unless you paid extra when you bought it for additional coverage that covers accidental damage.
"If still under warranty then send it in for warranty repair."
You can often have that done by a local place that is authorized to work on Dell computers without having to send it away from where you live.
If the only thing wrong is the optical drive will not work properly, there are lots of clone drives available for a reasonable price on the web that are compatible with being used in your model