What is the difference between socialism, communism and Marxism?

Also, is Marxism just pure, uncorrupted communism?

Its a difficult question to answer, the first post did a pretty decent job, but their are many forms of socialism, as well as communism. Marxism is more socialism then communism. And technically the world hasn’t seen any of the systems of government used in an actual nation(Russia and everyone they converted were fascists poising as communists. Socialism uses something called Use-Value, where as capitalism uses something called Exchange-Value.

Use-Value means you get out what you put in simplified terms, if your lazy you won’t get anything, but if you work hard you get out what you deserve. Capitalism seems to do the same thing, except your boss will usually make more money off you’re labor, and sometimes hard workers can’t find a job or a good one. (also socialism doesn’t use currency so the word afford doesn’t mean quite the same thing.)

Marxism is similar to libertarian socialism except Marxism requires the government to make the transition to Marxism, where as Libertarian Socialism makes the transition without government. Most of the differences are subtle or are around how they get to the system, for the most part each system is similar when it gets to its "pure" state.