You probably inadvertently set something that caused the problem.
I suggest you reset the camera to factory settings.
Grab your Instruction Manual and turn to page 100.
"Reset to Default"
..
My Canon Digital Rebel xti used to show f-stop, shutter speed, etc. in the viewfinder, but now it does not. I don't know if somehow I accidentally turned it off or not, but I can't find a reference to this in the user manual. Does anyone have a clue as to how to turn it back on?
Thanks!

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