Type a new  addressee in a new mail in Outlook Express 5.50
running on W 98 SE and send it .Now highlight the message in " Sent
Items " , right click on it and choose : add sender
to address book.If I repeat this then  another window pops
up and tells me that the address is already in the address book. BUT I
cannot find this email address in my address book, I searched and
searched. Please help where is it and why is it not IN
my address book?

katan-ga,

The email, for one reason or another, may be saved in a different user
profile and thus not displayed.  Click Start > Programs > Accessories
> Address Book
You should see ALL the emails in your address book.  Goto Edit > Find
People and type in the email address you want to find.  It SHOULD come
up...try that out and see if you're successful.
If it is, you can right-click > copy and paste it into the profile you
normally use.

-Tox-ga

Hello toxga
I have just done all that without success.

I should add that I also have Outlook XP (which I only use for contact
synchronisation with my 9210) but that the address book there equally does not
contain the mysterious email addresses.

Type a new  addressee in a new mail in Outlook Express 5.50 
running on W 98 SE and send it.

Now Open the message in "Sent Items", 
Highlight “TO:” and right click on it and choose: “Add to Address
book” or “Properties -> Add to Address book”

Now you User added in Address Book

katan-ga
Right-clicking on a sent item and going to "Add sender to address
book" will only attempt to add your own address, hence the message
"This contact is already in your address book" (if it is), and why you
can't find the new contact's address.
Hope this helps,
Boris

ustasga and boriskga , thank you very much.Can I credit you or are you
just friendly people making intelligent contributions ?