It sounds like you would benefit from a copy of your 401k's Summary Plan Description. This document explains your plan in plain English, and you were suppose to receive a copy when you first signed up for participation. Among many other things, you will find which options are available to you for "cashing out" of your 401k, including penalties and fees (which is another topic, but something you should seriously consider).
There is one more document that may help you, which is called a Plan Document. While the Summary Plan Description contains a brief outline of your plan’s key features, the Plan Document is a long-winded, full description of how your 401k plan is constructed. This is not written in plain English, so reader beware!
If I were you, I would start by asking your company administrator for a copy of the Summary Plan Document.