Research:
In here, https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=how%20to%20say%20never%20in%20mandarin It says that to say never, you say, "Cónglái méiyǒu", but another website, which is this one, http://eteacherchinese.com/Chinese-Dictionary/never-0 says that you should say, "cónglái méi", so, how do you say 'never' in Mandarin Chinese?
There is seldom a one-on-one word translation that will work in all contexts. "从来没有 | cónglái méiyǒu" or "从来没 | cónglái méi" works if you're talking about something that has never happened up to the present time.
我从来没学过中文. (Wǒ cónglái méi xuéguò Zhōngwén - I have never learned Chinese.)
If you want to talk about the future, as in "something will never happen", you need a different expression altogether.
他永远不会来. (Tā yǒngyuǎn bù huì lái - He will never come.)
So, my suggestion is, if you're looking for a word meaning, at least provide a context.
Short answer: as a native speaker, I recommend the first one
Long answer:
You can use the first one in almost all scenarios ant it would sound okay. The second one is more commonly used with in a sentence before the verb, but if "Never" is the full response of a question, the first one would be better. I think this is because the second one is the shortcut for the first one, but in as a sentence itself, it would sound a bit unnatural to me, not that it is wrong or others won't understand you.
从来没有 and 从来没 are the same thing
我永远不会... would mean: I will never...
You use that when you would never do something.
Ex. 我永远不会玩足球。 （Translation: I will never play soccer.)
绝不 or 绝对不会 or 绝对不干
I think 绝 more closely conveys the sense of "never".
