difference between I've ordered and I ordered

[Dezthumper]

I see many emails every day with I've ordered..., or I've emailed..., and think that instead, it would be better to write "I ordered...," or "I emailed...."

Is there a true grammatical rule that would help clear this up? I looked for over an hour, all over the web, for this type of information.

This has bothered me for years. I'm looking to the professionals - please help.

[Cerberus™]

This page gives some examples while explaining the difference in a very concise but clear manner:
http://web2.uvcs.uvic.ca/elc/StudyZone/410/grammar/ppvpast.htm

Many also have difficulties with the difference between present continuous and present simple:
http://web2.uvcs.uvic.ca/elc/StudyZone/330/grammar/simcon.htm

[Rfaleet]

I've order(present perfect) I ordered (past simple)
The simple past can be used with expressions which signify a definite, particular time in the past.
I bought a car yesterday.
I have bough a car yesterday. (wrong)

Another difference,
I emailed (action happened and finished in the past )
I have emailed (may be I can send another emails today)
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[Dezthumper]

Excellent! Thank you. I really appreciate the replies and so quickly at that. Thanks all!

[Rosario]

Hi Cerberus,

Thanks a lot for the website. Its really help me.