Troubleshooting a system 7 'book is not very different from doing same on a system 6 'book.

In your case, the problem might be as simple as a flat pram battery. Keep the thing plugged in and let it charge overnight. If you're lucky, all will be well in a day or so.

If that doesn't do it, post back, and lots of folks will pipe up with many additional suggestions (power manager reset dance, ritual sacrifice of free-range soy, etc.)