Free Will

I just learned something new in philosophy today.  I learned that there is no such thing as free will.  There is a view called determinism.  I'm not saying that I believe in it, but it does rais some very important questions in my mind.  Determinism basically says that there is no such thing as free will, and every action we take is caused by something else before it.  Take for instance stepping on a cat.  We would like to believe that we have the free will to choose for ourselves whether or not to step on the cat, but determinism says something different.  Determinism basically says that the choice to step on the cat or not is already determined because of other things that led up to the event.  As a child you may love cats, so your choice is to not step on the cat because you like cats.  On the other hand if as a child a cat killed your mother you would defiantly step on the cat.  It's kind of weird and eery feeling to think that everything we do is already pre-determined because of other causes in the past.  It makes sense though, all of the actions we take are based on our life experiences.  But how did it all start?  What was the cause before the cause and does that make us responsible for any of the actions we take?  Determinism raises an interesting question:  If there is always a chain of causes causing the causes, then should we have any moral obligation for our actions?  Some would answer no, and I might agree.  I think that even-though there is actually no moral obligations for our actions, we should act like there are.  What do you think?  Is determinism true?