The information relating to all my photos in "My Pictures" has always appeared in the bar at the bottom of the screen when I highlight the thumbnail. This includes aperture, shutter speed iso etc. This information has suddenly disappeared and all I now get is the file size in a smaller bar. I am using Vista.
I suspect that the details pane has accidentally been made smaller. Go to the top of the bar giving the details and when you get the double pointed arrow widen the details pane until you get everything shown again.