If you wanna get your friends password then you ned to install a trojan in his computer (google it) or brute force his email account (difficult) or sniff his network and see all packects leaving his computer.
Read read and read man, buy books, read websites and thinks like those and then after a couple of months if your brain makes a click with all that information you will have gotten you will know you are ready to start doing a little hacking lol
Sorry i was kind of rude but you know i prefer to tell you this things than letting you hack somebody without really knowing something about how to protect yourself and they you get caught. Now if i am not wrong i think you are just starting with all this hacking thiing then once again use google more often and websites such as, they even got videos which makes everything easir for you to understand but of course you need to know certain things otherwise, your mouth will be open and your brain y=will be wondering about what the is the guy talking about. type thing such as cain and abel tutorial or you know things that are related to the topic.
no offense but if you didnt know that about the antiviruses and what a hash is then i think it is not time for you to use hacking programs, use them until you got more knowledge about the subject, use google more often. Now if you wanna use brutus or cain then disable your antivirus while you are using those programs. im not saying that there are not gonna be websites in which you will get real viruses but usually if you get the program you want from the original website that created it then you will not get a virus.
Look man there are antivirus that dont like password crackers or any other hacking program thats why you get those messages from your antivirus and they will even delete them.