So, if you press the NUMLOCK key, it doesnt respond with a light? If that is the case, then it is hung and you need a technician.
If it does respond, then hit CNTRL-ALT-DELETE and start task manager. In bottom of window, there is a NEW task. Press that and TYPE EXPLORER and
hit enter. Let us know if the Icons load. If they do, then restart in safe mode, or get a CMD prompt and type MFC /SCANNOW.