Opening the archive

I’ve always had Outlook automatically archive my old emails. Now I need something from my archive. How do I access my archive?

The archive file is actually just another pst-file. If it doesn’t show in your folder list yet, you can open it via File-> Open-> Outlook Data File…

Most likely the file you need to select in that dialog is archive.pst but you can verify which pst-file you have been archiving to via;
Tools-> Options…-> tab Other-> button AutoArchive…

You really should not use the “Import and Export…” option to access your archive. This will put all the mail back into your original mailbox. Besides the fact that this could be a long and tedious process, eventually these will get archived again and you’ll end up with duplicates in your archive.