After upgrading from 13.10 to 14.04 my screen constantly fades to black. How to fix?

I have an NVIDIA 8600GT graphics card and am currently running the X.Org nouveau display driver.

When I boot I get a normal 14.04 login screen with no issues. Once I log in I see my desktop as expected. Then when I click on the Unity menu icon in the top left the menu flies out as expected but the screen darkens a little over and over until I have a blacked out desktop. Mouse cursor remains normal though.

If I right click about the screen sometimes the right click menu with jog the desktop into visibility again but then it quickly reverts to the blacked out state.

Does anyone know of a fix for this issue?