The following information is taken from: http://web2.uvcs.uvic.ca/elc/studyzone/410/grammar/ppvpast.htm

The present perfect is used when the time is not specific: I have seen that movie already. (We don't know when.)

The simple past is used when the time is clear: I saw that movie on Thursday. (We know exactly when.)

The present perfect is often used when giving recent news: Martin has crashed his car again. (This is new information.)

The simple past is used when giving older information: Martin crashed his car last year. (This is old information.)

My question is:

Which of the above tenses should be used to tell about past action, that needs no time specifying? I just want to tell about something that took place in the past, no matter how long ago.

Perhaps both are fine, but I need assurance. Thank you in advance.
Hi Dominik,

I'm interested in what your answer was, but unfortunately I don't speak Polish. Is it possible for you to provide an English translation of things you write, next time? That way, other people on the Forum can learn from and comment on your ideas. Emotion: smile

Best wishes, Clive
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I wish he provided us with an English version. His explanation is clear and quite interesting, makes things clear.

Thank you
Hi, Clive
It's high time you learnt Polish. Emotion: wink
But seriously, my English isn't very good so it was easier for me to write it in Polish.

Generally it can be said that:
If you give the date you use Past Simple
If things happened in the past but you don't know exactly when or it doesn't make any difference when, you can use Present Perfect.

The Present Perfect is a present tense. It always tells us something about now. If you want to emphasize the connection with NOW you use Present Perfect. If you don't want, use Past Simple.

Do not use the present perfect if there is no connection with the present (for example things that happened a long time ago)

I lost my wallet. (I lost it in the past. We don't know if he/she has it now)
I have lost my wallet. (I don't have it now and for example I can't by a present for my girlfriend)

Besides, Past Simple is often used instead of Presnet Perfect in AmE.