It's been 4 hours and the ball keeps spinning. Can I stop it? will it revert back to where it was? (X5.8) Of course i didn't do a Time Machine back up I guess I will just let it keep running all night and see what happens. If it doesn't install will it quit and say unsuccessful? I called and researched all the specs before upgrading and supposedly 1 gig of memory is all it needs. I recently ran all software upgrades. i have enough free space. My goal is to put in 4 gig memory and then the newest Lion which they said would run on this macbook. I did have the Optical drive replaced last year and don't use it much so I don't think it's that.