Since this sounds like a SMC update gone bad, you may be looking at getting the logic board replaced here.
First though, go to Apple's support site and look up on how to reset the SMC on your particular model. Try that first, and if it doesn't solve the problem, then you'll have to take it in to get the logic board replaced.
Since it's only about a week old, and thus within a pretty standard 30 day return period, if you requested they just swap it out for a brand new unit I would say you stand a pretty high chance of success. Worst case scenario you're looking at probably 3-5 days to get the MLB replaced.
Yesterday I was prompted to install new software updates on my new (1 week old) Macbook Pro.. It went through the process of installing new firmware with the normal 'dont touch whilst installing' warning,it then did the grey screen with tracking instalation bar and then asked to be restarted, which I did!
Now it just sits there with a grey screen and the fan on full spin! It did this for about an hour before I decided to shut it down.. Still doing it this morning with no signs of starting up.. Help please!

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