How do I import my address book (contacts) in to Outlook email?

I have recently upgraded my computer, and have transferred all of my contacts
in to Outlook, as I had previously in my former computer. Although all of my
contact information is visible in the "Contacts" section of Outlook, if I
switch over to my "Inbox," and begin addressing a new email message by
clicking the "To" button, no names from my Outlook address book are visible.
As such, the only way I can send an email to someone is to manually type in
their email address. I used to be able to "point and click," from all of the
names in my Outlook Address book, but now nothing is there. Under the
"Select Names" tab, there are two choices - "Contacts" and "Outlook Address
Books." Neither choice shows any information below. I don't understand why
the Address Book and the Email Function are not working together. Anybody
have any clue? Thanks in advance.