Looking again at your screenshot I can see what the problem is.
It looks similair to my phone when I have the cover on it (S view)
It look like this:
My guess is that you have a hardware failure. It looks like the sensor that triggers it mailfunctions. Also I think that the digitzer is broken. I don't think it happenend after a flash, seems really unlikely.
Sounds more like just failing hardware or maybe even water damage.
Originally Posted by trein91
EDIT: Btw, when I'm on touchwiz, It shows the "select language" page for a split second, before showing the black screen with the clock widget.
Samsung Galaxy S 4 I9505 | WanamLite v3.0
Samsung Galaxy S II I9100 : AOKP 4.2.1
HTC Touch Pro2 | ROM: Valkyrie 6.5.23115TR2.5
HTC HD2 | DarkStone1337 [FroyoStone Sense - V3.2]
HTC Desire : Oxygen v2.1.3