I learned a lesson when purchasing hardware from ebay. Make sure what you are getting has genuine equipment. Clones are ok but when you have trouble, you are usually stuck with a piece of junk. I recently bought an arduino pro mini clone that came with a usb to serial converter which has an FT232RL chip from ftdichip.com. I plugged the adapter into my usb port and the drivers did not load for it. After a few days of research, I contacted ftdi support and sent them a screen shot of their usb view software and they confirmed that the device indeed has a NON-GENUINE ftdi chip.
I purchased a nano clone from amazon.com from phantom yo-yo. I used it a few times and had great luck with it. Then over the weekend it stopped working. The same issue here, fake ftdi chips. Money wasted. Here is the one I purchased: http://www.amazon.com/gp/product/B00ALDKOX4/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
If you are concerned with your FTDI hardware, send them a screen shot of the usb view to email@example.com. They will respond promptly.