Why won't computer recognize usb device?

How do I make my computer recognize the USB device?

• I'm using an external memory card reader that plugs into the USB port on my desktop computer (Dell). It used to work fine, but now when I plug it into my computer is bings like it registers it, but no icon shows up, and Windows doesn't find it in devices. I've tried all the ports and I've tried restarting the computer. Thank you.

• Answer:

  this might help you. your USB ports may need to be reset. first to explain, the motherboard is where all of hardware of the computer is connected to, including the USB ports. Sometimes the motherboard needs to be “rebooted” also because something can go wrong, i.e. all your USB ports suddenly stop working. The small microprocessor on the motherboard will reload the drivers and your USB ports should be back to recognizing all devices! to achieve this simply power down you pc as you normally would and then unplug it from the wall for about 2 minutes. plug it back in and power up. hope this works for you.