Is it right to say "I have seen this movie last week"?
or should I say "I saw ..."? When is "have done" used and when is "did" used? should i say "see a movie" or "watch a movie"?I find in this article: http://unenlightenedenglish.com/2010/01/saw-vs-seen
"... For example, saying “I have seen the movie yesterday” would be incorrect. The verb form is being used correctly (“have seen”), but the word “yesterday” refers to a specific moment in the past–it does not connect the past to the present ..."

Question

Is it right to say "I have seen this movie last week"?
or should I say "I saw ..."? When is "have done" used and when is "did" used? should i say "see a movie" or "watch a movie"?I find in this article: http://unenlightenedenglish.com/2010/01/saw-vs-seen
"... For example, saying “I have seen the movie yesterday” would be incorrect. The verb form is being used correctly (“have seen”), but the word “yesterday” refers to a specific moment in the past–it does not connect the past to the present ..."

Answer

I saw a movie last week.

Answer

You can say 'I have seen this movie' or 'I have watched this movie' but you cannot use 'yesterday' or any specific past time expression with the present perfect tense. If you use past time expressions you must use the past simple tense. I saw this movie yesterday.' 'I watched this movie yesterday.'

The present perfect (have/ has and the past participle) is used either a) for actions or states that started in the past and continue to the present moment. 'I have lived in London for ten years' (= I still live in London) 
b) for actions or states that happened in the past but have a result in the present. 'I have lost my keys (= Now I have no keys) 
c) for actions or states which have happened at some point in our lives and the emphasis is not on when the action happened but only on the fact that it happened. 'I have read  War and Peace.' ' I have seen the film Memories of a Geisha three times.'

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我上个星期看过这部电影 "I saw this movie last week" or  "I watched this movie last week"

Answer

Your reference is exactly what I'm getting at.

The "have done" thing functions to describe how past actions effect the right-now moment. Right the point you're talking about it. That's why the textbook says "have seen it yesterday" doesn't make sense. Every have-done virtually implies rather "have done (by now)" than "have done yesterday".

Let's go to the movies, I heard "On Stranger Tides" is good.

Sorry. But I've just seen it (just now, by now, by the time you are asking me to see it right now).

I thought you watched it yesterday.

I had seen it the day before yesterday. (Here is how "had seen" has to be used. ie I had seen it BY sometime in the past, rather than "by now" as in "have seen it (by now)". )

When it's not very necessary to emphasize "how past actions effect the current situation", like your initial example, you won't have to use "have-done", so "saw" works here, too.

Answer

It depends on the situation, but I would say; "I watched that movie last week." 

'Watch' is used instead of 'see' when it comes to movies;
If you have 'seen' a movie, you may have seen the cover/poster/etc.
But if you have 'watched' a movie, you saw the actual movie.