I'm currently having the same problem. There are two main reasons.
1. Your card is not formatted
Solution-Go into My Computer (depending on your operating system) and find the drive that you inserted it to right click and then left click on format.
Note-If you format your card you will lose all data on that card.
2. Your device does not have the proper drivers needed to work with your card. Go to the companies web page that makes your brand of memory card reader and reinstall the driver.
Note-Sometimes when you reformat your hard drive or upgrade your Operating System you must reinstall all drivers on your lap/desk top
1. Your card is not formatted
Solution-Go into My Computer (depending on your operating system) and find the drive that you inserted it to right click and then left click on format.
Note-If you format your card you will lose all data on that card.
2. Your device does not have the proper drivers needed to work with your card. Go to the companies web page that makes your brand of memory card reader and reinstall the driver.
Note-Sometimes when you reformat your hard drive or upgrade your Operating System you must reinstall all drivers on your lap/desk top
