Card cannot be accessed. Reinsert/change the card or format card with camera
Really this is The Worst Message any Photographer could Have ! First, I own Canon T4i/650D , I was photographing a concert and suddenly this message appear on the screen and memory card can not be read !
I Tried to insert my SDHC memory in the laptop to check the all day images I photographed , But I shocked that all my files are gone as it ask me to format the memory on the laptop too !
Imaging how all your daily photos can be deleted without any warnings !
I have this memory card : Dane-Elec Pro 8GB 200x Class 10 SDHC Memory Card Its Working well in most of times , but this message appear suddenly after long period of photographing ..
I really need your help , is it memory problem , or the card slot pins in my canon T4i . Share your experience :)
Sorry for my bad English .. Thanks in Advance, Amro.

@MichaelClark I forget to mention that I Tried to recover the deleted photos using recover software , but it recover older images and not the images that I lost the last time !
– Amro Ashraf Mar 13 '13 at 14:22