My friend installed Bittorrent and got viruses on her mac

So my friend wanted to watch "50 shades of grey" (I know) and so I showed her how to install Bittorrent and download a torrent file. 2 days later (today) she messaged me saying that her browser settings have changed, the mackeeper icon is in her dock and that she couldn't even open google drive. I am mostly concerned about the mackeeper icon since I have heard very bad things about it. What is going on?? This didn't happen to me (also on a mac). How do I fix this without any kind of damage?