How do I view the internal hard drive contents?

Sorry for asking such a basic question, but everything seems to be 'hidden' on a Mac! In Windows you just go to 'My Computer' & you can view the contents of the internal hard drive; all the program files; everything that makes the computer work; all the files you've stored on there, etc. I have looked everywhere on this Mac & there seems to be no way of viewing this. NB: What I'm trying to do is delete the irritating Norton toolbar that comes up every time I open Firefox; it should be in a folder somewhere but I cannot even see the hard drive right now! Any help much appreciated; have searched endlessly on forums etc & can't find anything at all. Thanks.