After you get your address book rebuilt export it to a csv file. Then copy this file to a floppy or CDROM. Next time you have a problem it will only take 2 minutes to get them all back. I use a hotmail account and just email anythin I want to save to it. Email you address.csv file and you can rebuild you addresses from anywhere!
Also, most mail clients have an option to leave mail at the ISP. If you use this option all of your email is stored there even after you download it to you computer. I believe all ISPs have web-mail so as soon as you get another computer or find anyone computer to use you can bring up IE and contiue business.
Example would be to go to
www.verizon.com or whatever and look for a link to click that says webmail or user login. Click the link and you are in business. The other option would be to just use hotmail or any of the other thousands of free email accounts and you're good to go no matter what.