My Esplora I got about 3 months ago has been fine, and I have used it for multiple projects before. Today I wanted to make sure my Esplora was working, and a strange thing happened; every time I plugged my Esplora in my computer, I can hear the sound that you get when a driver is plugged in, and made the unplug noise shortly after I plugged the Esplora in. The Esplora's port that I set up is recognized, but the port is only recognized when the (L) light on the Esplora is on. I hope I dont have to buy another Esplora, and I hope there is a solution. =(
Have you tried another cable?
I have tried 3 different cords, and the same results happened. At this point I feel like I may need to get a new Esplora 
There is some info on reflashing the USB chip here Is my UNO Fried? - Installation & Troubleshooting - Arduino Forum I don't know if it will help but you may wanna give it a try.