Card reader Problem ?

Hi All
Yet another newbie here looking for help
been downloading games dropping them onto Micro SD card no problem recently, but today put SD card into the reader and it won't recognise that card is in the reader but when you put the card back in the Ds all the games are still on the card can anybody help tried 3 different micro sd cards all have games on but PC can't read them now.Thanks in advance if anyone can help

try using a different card reader

Done that still no JoyThanks anyway

Try a different PC :)