If a USB port on your PC is not functioning it may be because the operating system has disabled it in order save power. You can re-enable it by following these steps.

1. Press the Windows key, plus R, and type in regedit. Press ENTER and your Registry Editor will open.

2. In the folder tree to the left, browse to HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ services \ USB - if the USB folder doesn't already exist, you can create it.

3. On the right, right click on the file named 'DisableSelectiveSuspend' and choose Modify.

4. Set the Value Data to 1.

Now after restarting your PC, the USB ports may be reactivated if they were disabled to save power.