Latest Yosemite Update Doesn't Look Right

[longdrag]

Hi,

I had a message through the App Store which said a Yosemite update was available. I Selected it and the screen is now black and the cursor arrow is showing.

The keyboard is lit but then it all goes dark. If I click the trackpad it lights up again but nothing else

Any clues? Or ideas as to what I can do?

Thanks

 

[pickaxe]

It's the new Yosemite dark mode.

 

[grahamperrin]

It's the new Yosemite dark mode.

Speak up please. I can't see a thing.