Do you have problems with devices connecting and disconnecting from USB without reason?

Have you used one USB port some day and another one doesn't operate?

Follow the procedure bellow in order to test for sure if your USB ports are operational under Windows 7 / 8.x

Go to "Control Panel --> Power Options --> Change advanced power settings

Drop down to USB Settings --> USB selective suspend setting and change "Setting" from Enabled to Disabled.

Click "OK" and check your USB ports again, using a USB stick or another USB device.

NOTE: You must make the same settings on all power profiles you use.