These drives only last for so long. You can try to run one of those laser lens cleaners in the system or even go as far as to open and clean the lens(very easy on laptop drives) with a qtip and rubbing alcohol(very gently and with the system off. eject the drive tray first then shut down to clean.).
If this does not help they drive may just be failing. If under warranty contact Dell, if not either get it replaced(you can do this your self as well many times) or use a usb external drive(get the notebook ones so you do not need extra power).