Honestly man, the Dell OEM Ubuntu is garbage. It has kernel 3.13, and the current is 3.19. For someone who isn't experienced with kernel upgrades, you might want to consider flashing to a stable Ubuntu release. I made a post a couple days ago with my step by step flashing process, since I was so fed up with how Dell built their OS.
Plus their recovery app is garbage too. If there's anything you want to preserve, i would suggest installing Deja Dupe to backup your /home/ config.
A clean, stable install with a nice fresh kernel does wonders.