ranaasad910 :
The gallery doesn't show pictures or video files but when i insert the card on the computer it shows the files!!
So issue is just the gallery, that does not mean much. You said that in File Manager the card shows empty though. If you go to File Manager, then browse to the DCIM folder, do you see your files in there? For the Gallery you just need to point the photo app to use the SD card and possibly in the settings of the image viewer. Your post made it seem like the phone actually did not see the card as having files on it.