My Nikon D90 is not giving any Viewfinder Info Display across the bottom. How do I turn it back on?
You could first try resetting the settings of the camera by doing the following: Press the two buttons with the green dots by them, AF Mode and Exposure Compensation button. Hold them together at the same time for a few seconds. This is also in the manual.
If that fails, it is likely an issue that you have to send the camera to a Nikon repair facility for. This seems to be a somewhat common issue that others have had. Nikon ended up repairing faulty wiring it seems. See: