After you inserted your USB WHAT ?????????????
If you plugged in a USB stick drive or an iPod or the like, then I would suspect a fault in this device has overloaded the USB system.
First thing to try is to unplug all usb devices and cables and boot the machine. Yes I know you will not have a keyboard.
If you get into windows, then plug in your keyboard and mouse. They may auto start. They may not. If they start, then shut down windows, and then plug the rest of your USB items in - except for whatever it is that you plugged in when this started.
See if all is well. Then you need to decide if you plug the offending device in again to see if the same thing happens again. If you do and the same problem happens, stop using this device until it is replaced or repaired.
If the unit won't go on, then try to boot into safe mode by hitting the F8 key once every second from off. You will see a screen load that give multiple options, you want safe mode with networking.
Wait for the system to load - this will take a very long time, and will look completely different from what you are used to seeing.
Once in safe mode, go into the control panel by hitting Start, Control Panel, System, Device Manager.
Scan down the list of devices and see if there are warning signs on the USB ports. You may have to uninstall the USB ports and reboot the machine to get then to turn back on. The ports should automatically reinstall at boot up once removed.