I am having the white-screen problem too. I also am a novice and trying to figure this out!
I was using the Genesis Family Tree child theme and could not customize it – got the white screen. I have tried turning off all plug-ins, I still get the white screen AND I am not able to install any other themes.
So if disabling the plugins doeesn’t cure the problem, and switching to Twenty Thirteen doesn’t solve it, what would I try next? It would seem that it’s not the plugins or the theme.
I’m so confused :(. Any help is so very appreciated!
