Can't figure out when americans use present perfect! Please give me some easy rules!?

My choices in blue.  These are very arbitrary; there's no real-life situation given as a context, so I might use the other one in a different situation.

Did you lock the door?(or Have you locked the door?)

"It's so cold!"answer: "I've opened the window! or I opened the window!

I've lost my keys! or I lost my keys!

At the doctors: I've broken my arm! or I broke my arm! also will he ask you: Have you broken your arm or Did you break your arm!

Did you finish your homework or Have you finished your homework? When you're finished: I've finished my homework or I finished my homework!

I've attached a picture or I attached a picture to the e-mail!

He's fallen asleep! or He fell asleep! (when's asleep now)

He's gotten up or he got up! (when he's awake now!)

My address has changed! My address changed!

Yumi, the movie started or Yumi, the movie has started!

I've changed my address! I changed my address! (now it's different!)

I've intalled windows XP or I installed windows XP!

____

In general, use simple past when you're thinking of the event as dead and buried.  Use the present perfect when you think the event still has some chance of  influencing the present state of affairs.

CJ 

CalifJim

“It's so cold!"answer: "I've opened the window! or I opened the window!
”

CJ, If you don't mind, could you give me context for both of the versions? I don't see any difference between them.

Hi, YSchneider. I am not a native speaker and this is indeed a tough grammar point for non-native speakers.

Here is an extract from CGEL*:

Did you lock the front door? [5]

in a domestic situation where it is known that the front door is locked at bedtime every night. In that case, [5] is more or less equivalent to Did you
lock the front door at bedtime? (Incidentally, in [5], "the" in "the front door" is another case of situational definiteness; cfS.Uff.)

--

The ATTITUDINAL PAST, used with verbs expressing volition or mental state, reflects the tentative attitude of the speaker, rather than past time.
In the following pairs, both the present and past tenses refer to a present state of mind, but the latter is somewhat more polite:

Do/Did you want to see me now?
I wonder/wondered if you could help us.

--

Where did you put my purse ? [ 1 ]
Where have you put my purse? [2]

The purpose of both of these questions may be to find the purse; but in [1] the speaker seems to ask the addressee to remember a past action; while in [2] the speaker apparently concentrates on the purse's present whereabouts. There are many such cases.

--

Leaving aside such virtual equivalences, we may now focus on the difference between the two constructions, contrasting the meanings of the simple past given in 4.14 with the following meanings of the simple present perfective:

(a) STATE LEADING UP TO THE PRESENT

That house has been empty for ages.
Have you known my sister for long?

(b) INDEFINITE EVENT(S) IN A PERIOD LEADING UP TO THE PRESENT

Have you (ever) been to Florence?
All our children have had measles.

(c) HABIT (ie recurrent event) IN A PERIOD LEADING UP TO THE PRESENT

Mr Terry has sung in this choir ever since he was a boy.
The province has suffered from disastrous floods throughout its history.

Of these meanings, (a) corresponds to the 'state past' use of the simple past, but differs from it in specifying that the state continues at least up to the present moment (cf: That house was empty for ages - but now it's been sold); (b) corresponds to the 'event past', but differs from it in that the past time in question is indefinite rather than definite (cf: Did you go to Florence (last summer) ?); (c) corresponds to the 'habitual past', but, as with (a), the period identified must continue up to the present.

Note In AmE there is a tendency to use the past tense in preference to the present perfective, especially for the indefinite past; eg: Did you ever go to Florence ? (c/4.13 Note lb], 4.22 Note [a ]).

--

Have you seen the Javanese Art Exhibition? [yet]
Did you see the Javanese Art Exhibition? [when it was here]

The first of these implies that the Exhibition is still open; the second that the Exhibition has finished. From this concern with a period still existing at the present time, it is only a short step to the second implication often associated with the present perfective, viz that the event is recent. The simple present perfective is often used to report a piece of news:

_., , > the news? The president has resigned.

Because of this connotation of recency, B's reply in the following exchange must be considered absurdly inappropriate:

A: Has the postman left any letters? B: Yes, he did six months ago.

Since postmen in general deliver letters daily, the implicit time zone in this case would be no longer than a day.

[Note] In AmE, the simple past is often preferred to the present perfective for the variants of the indefinite past discussed in this section. Compare [6 ], for example, with Did the children come home yet? <esp AmE). Other AmE examples are: I just came back; You told me already; and without an adverb: /*m tired -1 had a long day.

* A Comprehensive Grammar of the English Language (Quirk et al.]

YSchneider

“ One example give really confuses me a lot, that's the I('ve) attached a picture(to an e-mail) thing. I've seen this so often in e-mails from american companys and it was always writen with I have attached, but in my present perfect concept I'd rather choose I attached.”

Hi YSchneider

Yes, that's one of the sentences I might disagree with CalifJim about.  If I were typing out an e-mail and wanted to tell the person that I was sending an attachment with it, I doubt that I would use the simple past tense.  I'd probably use either the present perfect OR the present continuous.  I'd say the reason for that is probably the extremely close connection with my present activity (typing out the e-mail).

I'd also say there is an element of truth to the fact that the present perfect sometimes sounds more formal -- but only an element of truth.  I would not be willing to say that is always the case.