bu4不means 'not ; do not' while mei2you3没有means 'do/did not have/has ; did not' 我不是亚瑟。- I'm not Arthur. 我不想吃午餐。- I don't want（想） to have lunch. 我没有钱。-I don't have money. 我没有做这件事。-I didn't do this.

A native Chinese speaker will explain this better to you but, in the present tense mei 没 is used to negate you 有 and bu 不 for all other verbs. However in the past tense, bu 不 is never used to negate a verb, always use mei 没 or meiyou没有.

"bu" is a strong negation and is sometimes translated as "not". But the meaning can change depending on what word it is used with. It can only be used with present and future actions[it can't be used in the past] 明天不会下雨- It won't rain tomorrow [future] 我不去你家- I'm not going to your house 我不在家- I am not home 我不会踢足球- I can't play soccer, 你不可以进去-you may not enter, 我不能出来- I can't come out In these sentences "bu" along with the other words mean "can't"(note that "mei" cannot be used with "会" "可以" "能") It can also be used to ask a rhetorical question: 我不是告诉过你了吗- Haven't I told you already? "mei" is very different and can mean a few things depending on the context: "doesn't have/without" 我没有女朋友 (I don't have a girlfriend) "is not as..." 我没有他高 [I'm not as tall as him] -negates incomplete actions: 他没去医务室- He didn't go to the clinic. "mei" also goes with 过 (note that "bu" cannot be used with it) to show experience: 我没看过这本书-I haven't read this book/我还没吃过早饭- I haven't had breakfast yet. *note that "mei" can NEVER be used in the future, since it negates incomplete actions. Imagine saying "I didn't go to school next year"- It doesn't make sense. Here are the same verbs used with "bu" and "mei" to show you the difference: 不吃- don't eat/doesn't eat 不去-doesn't go 不喝- doesn't drink/don't drink 不看-doesn't watch 不做-doesn't do 没吃- didn't eat 没去-didn't go 没喝-didn't drink 没看-didn't see/watch 没做-didn't do. here's another example using the same verb with "bu" and "mei" 我最近不喝汽水- I haven't been drinking soda lately. 我最近没喝汽水- I haven't drank soda lately. The tricky part, is that in Mandarin verbs do not change depending on the context like they do in English. Take this sentence for example: 我不懂- I don't understand. If I wanted to say "I *didn't* understand" I would still use "不懂" [not 'mei'] 以前不懂- I didn't understand before. Or like in this sentence 我以前不喜欢她- I didn't like her in the past. Another thing that may add to your confusion is due to how different we speak in English to how Chinese speak in Mandarin. In English we say "I'm NOT interested in soccer" while in Mandarin, that same sentence would be 我对足球没兴趣 meaning "I don't have any interest in soccer" but it's translated as "I'm not interested in soccer" English, because it wouldn't make sense the other way.

Well...in most cases, 不(bu4) is used to negative all other verbs and adjectives. But 没有(mei2 you3) is used to negative 有(you3). The most significant different between them is 没有 covers such meanings: there is(are, was, were...) not sth. I(he, she, we...) have no sth. I(he, she, we...) have not done sth. You can say that 没有 in Chinese just works like "not be" and "not have" in English, and 不 is simply a "not" or a "no". You shouldn't say "不有" ! But there are exceptions: 1. When it coms to comparison: If you say sth is not as good as another thing, you can say mei2 you3: 这枝笔没有那枝好。 This pen isn't as good as that one. attention...in this situation, you should not say "不". "不" is "absolutely not". You can understand the difference between "This pen is not good." and "This pen is not as good as that one"? 2.When you would like to negative "必要"(bi4 yao4, means “have to”), you can use both "不" and "没有". 你不必这么做。=你没有必要这么做。= You don't have to do that. ......lots of situations...you will meet more of them in your study in the future.

I don't think there is confusion. Just study a little and you'll figure it out.