USB device
It may happen that in the Device Manager in Windows, the USB device appears with a question mark or a yellow exclamation point. This simply means that a device plugged into a USB port of your PC the computer is not recognized because the driver was not found by the system.
Identifying the device
Firstly, it is necessary to identify which device was not recognized. If you do not know, simply remove successively, one by one, USB devices plugged in to your PC
Solution
Once the device identified, it is necessary to obtain the latest drivers. Either the device has a driver CD or try searching them on the internet (using Google)
Once the drivers installed, just follow these steps:
Control Panel/Add Hardware
The Add Hardware wizard opens, just follow the instructions given.