Hey i'm new in Apple world and have some questions that hope you guys can help me with. 1) When i was calibrating the battery and when the battery got to low, i selected system preferences, and some apps didn't open, they stayed at the "loading" mode. Is that because the battery was too low or is some problem with my computer? 2) I heard rummors about youtube not working on mac, if i install Adobe Flash Player will work right? 3) Some people tell me i don't need to use anti-virus but i wanna use one.. What's the best one? 4) Is it ok to download megaupload files and watch them on realplayer mac version? 5) I have some files from my HP computer like music and videos, can i pass them and watch them on mac with no problems? Thanks and sorry for the trouble. My mainc oncern is with number 1), because i don't know if my computer is not working well.