About a week ago my mid 2009 MacBook Pro started acting strange. Safari will stop loading mid between web pages. Then the whole safari will freeze. And a notice says whatever website I visit may be harmful to computer. Then I can't move anything to trash because of error 50. A hard restart will temporary fix the problem for about an hour then it happens again. Everything is upgraded. Newest iTunes safari software. Didn't download any malware. Not sure what is going on. Anyone know?