SD card read but wont open

On my dell desktop computer, with windows 7, came with an sd card reader on the front.

When inserted the drive g changes from light grey to normal icon color so that it can now be right clicked and Open is an option.

But whenever i double click or click on open it says 'please insert a disk into removable disk (G:) .

What should I do?  it has pictures on it from a Samsung S850 camera and i really really dont want to format it because it warns they will be erased. HELP!