Past Simple or Present Perfect: Tried or Have Tried

I’ve tried to help you.
The action happened in the past but I don’t say when.

I tried to help you yesterday.

The action happened in the past but I say when.

1. Which is correct and which is not? I’m very confused!


2. Is there a simple rule to follow?

More Examples:

You can use the account that you’ve already created.
You can use the account that you already created.

I’ve sent you an email. Please check your Inbox.
I sent you an email. Please check your Inbox.

Answer

Which sentence is incorrect will depend upon:

1. The country you are speaking the sentence in.


2. Signal words you are using in the sentence &

In British English, the use of Simple Past and Present Perfect is quite strict. As soon as a time expression in the past is given, you have to use Simple Past. However in American English, you can normally use Simple Past instead of Present Perfect, so the following rules rarely apply to American English.

Signal words:

If signal words explicitly define that the event is in past, you have to use Simple Past.

eg.

1. yesterday


2. ... ago (an year ago)


3. in 1990


4. the other day


5. last .. (last summer) etc.

Example sentence: I phoned Mary 2 minutes ago.

If signal words do not explicitly define that the event is in past, you use Present Perfect.

1. just


2. already


3. up to now


4. until now / till now


5. ever



6. (not) yet


7. so far


8. lately / recently

Example sentence: I have just called Mary.

Source (Shamelessly copied word-to-word)