I tried deleting the light fog node (I'm guessing you mean in the hypergraph), but it didn't help. I did find that if I set the scale to 50,000 then I can see the fog. However, if I set any decay, the whole thing goes away and will not render.

Is there maybe a global setting somewhere that I have set that is messing me up?

So how bad is this 4.5 bug? Can I not do fog lights?