N card nintendo ds only blue screen

Question

hi
I have a N card and first it did very wel, but yesterday i put a game on it and when i came at 50% of the list the screen doesn't do anything and get stuck. I removed all games on the card and last save (someone says that) and put 2 games on it and know when i open it and when i click on menu, then i see something very quickly in the up screen and then all is blue (like normally but no games appear or something)
Can someone please help me?

Thanks :)