Everytime the box "Norton 360 performing background tasks..." pops up machine slows then freezes --- w 8.1 hp envy H8-1420t. 8 gb ram 64 bit. Been on chat twice. So far they did everything except uninstall. Had upgraded to 360 and for a few weeks everything was OK. My 4 other machines are OK but this one is the only one with W 8.1