[WIN8] Can't update from 8.0 to 8.1

Go to MS Store, click on update to 8.1. Tell me to complete Windows update first. Go there & find 1 important update ( & 1 optional). The Important one is for Win 8 64 bit based os. mentions that it's scheduled to do it automatically at set time. I do it manually & click install. I get the ok. Go back to d/l 8.1 & get same message re: need to update SAME UPDATE. . Do it multiple times. Tried shutting off auto update. same results.. What is the problem? I'd like to d/l 8.1........