You may well already know about this, but in case not: If you need to read your emails or send anything out, in a pinch you can access them online from a good mail website that I use as a homepage. It reads your messages right from the server, so they will still be on there when you do download them into your computer. You can also send and forward and cc. back to yourself any of your own correspondence, and send/receive attachments. All you need is your email address and your server password. The only thing to be aware of, though, is that if you delete something it will stay deleted, whereas if you merely read a message then close it again, it will land in your Inbox when you next download from your private programme. Also there are no filing facilities so you would have to leave everything in the main box. Not sure if they have any sort of anti-virus software running, so the usual cautions apply.

Mail2Web has bailed me out of trouble a few times when MY Outlook was acting up. (I second Stilly's recommendation of Thunderbird.)

http://www.mail2web.com/