Apologies if this has been answered before (I didn't find any exact matches).

I am running Ubuntu 13.04 64-bit on a Dell Latitude E6530. It appears my issue lies with Gnome 3.8.3. I don't have the same issue with Unity.

Essentially, the black screen (screen saver) activates randomly, and requires a number of key presses/mouse clicks to disengage. By random I mean not only when I'm away from my desk, but also while I'm working. Usually also at boot - I usually don't even see the login screen at boot. I am the only user so I can just enter my password and am able to login (the Desktop then appears as per normal)

I suspect it may possibly lie with the Nvidia card (system has a dual Intel & Nvidia setup)

I would appreciate any advice and assistance here. I apologise for the lack of information, but I honestly don't even know where to begin looking.