i updated last night and shutdown before i went to bed and woke today to check emails it wouldnt load. i was stuck in the white screen with the grey logo in the middle and the sturning gear below it. so ive been try to figuring out how to find out whats going on. ive done everything to fix it. i did the fsck in the command s promot thing and it said volume seems to be OK. but when i did boot when hearing the ding hold just the option button it went to a blue screen and had the macintosh HD logo in the middle with a white circle and a blue x inside of it on the bottom right of the HD logo. what does it mean? it looks like this... 
......dont just view and not reply please help! or point me into some direction! thanks
......dont just view and not reply please help! or point me into some direction! thanks