recover files from sd

Normally you would try data recovery software, but if the card is not recognized the recovery software won't recognize it either.

Try reading the card on a different computer or with a different card reader.
 


Have you tried what Phillip suggested?
 
Before doing all of that stuff, which can be time consuming, try the simpler things first. You should be able to plug in your camera to your computer with a USB while the SD card is in the camera. Set the camera to drive mode so it will register on the computer, and see if the card displays from doing that. Another option suggested above is a good one: try another computer. See if those things help before using recovery software. That is the answer much less often than these more simple things.