What is the difference between paganism and Wicca?

I was told by my friend who's Wiccan that their is a difference to quote his exact words: "pagan is bad, don't meddle with it." I take his warning with meaning and intend to fallow it but I want to know the difference between the two so I can fallow his advice, he says that the difference is: "pagan is a little more dark and involves a little heavier form of withcraft" Is that the only difference or is there more of one????