macbook and iPhones

I'm a newbie with mac products. I've had an iPhone 3 & 4 and now want to move up to iPhone 5 but I can't backup my info on my macbook. I just don't know why I can't even access the internet or even shut the macbook down to try and reboot it. I admit, I mainly use my PC for everything but would like to become more acquainted with apple. Would I 'hurt' anything by disconnecting the power cord and then trying to reboot...

Before pulling the plug (a very bad idea, by the way) what have you tried to shut it down? What error messages or just messages are you seeing? What is the version of the macbook do you have and what operating system is on it? What were you doing when it got hung up?