USB ports don't recognize memory sticks or external harddrive.

If your using a usb hub or similiar, try connecting directly to the front or the back of your machine.
Do you have another USB cable to try or is the usb connector directly on the USB device?

Try these steps to reinitialize your usb ports on your pc

1. Unplug ALL USB devices connected to the computer. If you are using a USB mouse and keyboard, temporarily use the older type PS/2 devices if you have them, if you don't then just leave them connected.

2. Hold down the windows key and press r

3. Type devmgmt.msc into the run menu and press ok

4. Click on the + sign next to the Universal Serial Bus Controllers



5. You might need another mouse to do this if you have a usb mouse.. I recommend you get a ps2 connector mouse which goes into the green round connector in the back of your pc.

6. Right click and uninstall first the usb root hubs. all of them then uninstall the rest of the devices you see under Universal serial bus controllers

7. Ones you have uninstalled everything you should see the Universal serial bus controllers there at all.

8. Now go ahead and restart your pc.

9. Ones you have restarted the pc your usb ports will reinstall in a moment stand by while it installs all of them. If you get warning messages click ok or continue installation.

10. Now go ahead and plug the usb devices back in. Install software if required, all usb devices if not faulty or broken should work now. Also note the error code if you get one?

This solution doesn't fix all usb problems so if you have a yellow ! mark there and device status reports a error code. Then it might not be a problem with your usb ports.