If you click on links or URLs in other programs and Firefox fails to open the target page, try to make Firefox the default browser.
If links still don't open in Firefox, see Setting Firefox as the default browser does not work - What to do.
Some programs are hard-coded to open Internet Explorer rather than the default browser. Some of these programs are:
- MSN Messenger
- AIM 5.9 - Upgrading to the latest version of AIM will allow you to open links in Firefox.