By Diane Poremsky
Following a number of exploits found in Internet Explorer, many security experts are recommending that users stop using it and switch to a different Web browser. As a result, many users have switched to Firefox, only to discover it didn't work well with Outlook, either opening two browser windows, or opening the link in a browser window and displaying the File->Open dialog box.
To fix this annoying behavior, you need to remove the check from Use DDE on the HTTP protocol. First, select Tools from the Windows Explorer, then the Folder Options->File Types tab.
Locate the HTTP protocol, labeled URL:HyperText Transfer Protocol and select it, then click the Advanced button. Select Open->Edit and remove the check from the "Use DDE" box, then exit back to the File Types dialog. Repeat these same steps for the HTTPS and FTP protocols.
Now Firefox should work as your default browser and get along with Oulook.