1:lug out the power chord and let it run dry, then plug it back in and restart.
HOWEVER this might not help, if it's a problem with the /C: (as in it freezing) it should help.
2: if that doesn't work try ctrl alt delete
obviously.
3: if neither of those work, or if you wanna try this one first try booting up the laptop, then press F5 (?) to go into settings and run on safe mode... (that's incase of a virus, but you never know if it solves your problem.)
not much i can say to help, really.