Hi Hendo, and welcome to the forum.
Yes, it is a problem. You need to uninstall the Norton application, and probably also have to run the Norton removal tool. http://service1.symantec.com/SUPPORT/norton2008.nsf/docid/2007082908475279?Open (Don’t worry about saving your product key.)
Avast might work correctly following these actions, or you may have to carry out a “repair install” (Control panle>add/remove programs>avast antivirus>change/remove then click “repair”)
Worst case you will have to uninstall both, run the Avast uninstall utility http://www.avast.com/eng/avast-uninstall-utility.html (download this first) possibly in “safe” mode, reboot, and re-install Avast afresh. Just be off line for the time you don’t have an AV installed during this process.
Outlook Express is not Covered by the Exchange/Outlook provider. This one is only for MS Outlook (the one from MS Office package).
Internet Mail provider will cover your Outlook Express. If you’re not using MS Outlook, you can install avast! without this provider…