Memory Card has no files on it, but shows its full

Just bought a new Ultra Plus microSDHC UHS-1 16GB card from Wal-Mart.  When I plug in the card reader into my PC, click on properties for the card, it shows 14GB of the 16GB is used.  There are ZERO files on the card.  Consequently, I can only record 2 min. of video from my drone. 

Please help!  Is the card faulty or can I fix it some how?

You could try formatting the card.