i need help my lol is not working

HI i have been since 2 months ( i was playing on my school computer) but since 2 weeks i cant no play anmore it is saying you Pvp.Kernel has stopped working. I tried everything i cant desactivate my anti-virus because of the admin rights i dont have the password. I really dont know what to do i need some help. i tried to put Lol on my flash drive but i still have the same problem i dont what to do