Hacking Cant find NDS & GBA card in S2

[rosette]

I accidentally pressed my DS & all my games are gone in my DS, but after checking on my computer the files & games are stiil there. On my DS I pressed the game & multimedia but they are all blanks & I pressed the Boot & it says "ERROR, cant find NDS or GBA card in S2 Do you want boot to NDS mode?". Please help me to restore again all my games in DS....

Thanks in advance.....