Mozilla Thunderbird

[#1]

My pc has XP, with Zone Alarm. I use Mozilla Thunderbird for my e-mails. Yesterday I received an e-mail from a relative to let me know they had changed their e-mail address. I couldn't find a simple way of editing my Thunderbird Address Book so that the senders address on the incoming e-mail could be electronically transferred to the address book. The Thunderbird Help Page didn't help. In the end I had to manually edit the address book entry, which isn't the most reliable way. I seem to remember that when I used Outlook Express, I could do this the electronic way
So now for Question No 1 - Is there a simple way of doing what I wanted to do?
I tried to ask Mozilla Support, but couldn't get past the log in window - it either didn't recognise my e-mail address or my password.. I re-registered with Mozilla, just in case that was the problem, but even after replying to the confirmion e-mail that I was who I said I was, that didn't get me past the log in window.
So that's Question No 2 - why can't I log in to the Mozilla Support page?
Thanks for your help

[#2]

Hi there
See here -  scroll down to  Editing a contact
http://en.flossmanuals.net/thunderbird/address-book-basics/
Regards
Mike

[#3]

Thankyou for that, but it still seems to me that , having opened the contact details in the address book, I have to type the e-mail address in, which is what I was trying to avoid. My typing is liable to introduce errors.
What I was looking for was something like having the e-mail open, then clicking a button or two which electronically put the senders e-mail address into the contact details.

[#4]

If you right click the the email address you can copy it which you can then paste when you edit the address book entry.

[#5]

When I " Reply to Sender Only"... the contact address goes into my "collected addresses"...automatically.....   you should find this as a secondary listing on your "Address book" .....( I have loads of "one off" addresses in there I must sort out and delete)...
once it is in there, just delete the old one....

[#6]

Sorry for the delay replying - hectic weekend - cub camp. All the preparation, then the surviving, then the recovery.
Thanks for your answers. I shall try them.