Go to control panel, power options, change plan power settings, change advanced power settings, scroll down to usb settings, click on usb selective suspend and select disable
Have u tried disabling the USB Selective Suspend in the power options? Worked for me on my desktop system. I had one in every 3 shutdowns not powering off the system completely leaving the fans etc on but turning off the monitor, keyboard, etc. Had to hold power button for 5 seconds to switch...