after clicking on "updates that are critical" the diaglog box goes and goes and goes and goes and goes and goes and goes and goes ..nowhere why do critical upda

for many days when i click on update firefox - critical etc. the screen bar never stops - i left for an hour and it still did not install the update(s) i have unexplained mini crahses and wonder if it is perhaps this critical update that won't update on my computer 64 bit windows 7 4 gig ram 750 had drive lenovo about a year old machine