When u say从来没有,u didn't try the thing before because it's new to u or u know it but u didn't have the opportunity to try and u are willing to have a try. 我从来没有吃过那个香草味的糖果。 However,you say从来不，it means the thing contradicts your own rules and u think it's bad to try,like drugs.Drug is a horrible thing,so u say " I'll never be addicted to drugs." Because u hate or dislike it,so u say"从来不" 我从来不和陌生人说话。

1. if you omit 来, the meaning is the same, they become 从没有 and 从不. moerover, you can also omit 有 in 从没有, it becomes 从没. 2. usually, you should use a 过 after 从没有, but never use 过 after 从不. 3. they both mean sth has never happened, or sb has never done sth. example sentences: 这儿从来没有发生过地震。// 这儿从不发生地震。 他从来没有对我笑过。// 他从不对我笑。 4. as daniel said, usually speakers put personal emptions into 从不, 从不 is often related with a negative determination. A. 我从来没有跟她讲过话。 i've never spoken to her. B. 我从不跟她讲话。 i've never spoken to her(because i didn't want to). my answer may be insufficient. to tell their difference and use them properly, you need a great deal of reading excercises.

从来没有means you haven't done something. e.g. 从来没有想过当教师，从来没有去过黄山。 从来不means a total negation to do soemthing, and related to determination. e.g. 从来不需要，从来不想去黄山。

as a native chinese , i can't find diffrence between the two words .At most time you can use anyone of them.It is too similar

从来没有= (I) never have, it is understandable. Example: Q﹕ 你有愛過我嗎﹖ A﹕ 从来没有 从来不? = (I) have never____, you need to fill in the blank. Otherwise it is not understandable. For example: 从来不(愛你) 。