If you’re an Outlook 2007 user and are planning to upgrade your system to Windows 7, then you probably want to backup your Outlook database file. This is especially true if you are planning to do a “clean” installation, where all the data on your hard drive is completely wiped off when the new OS is installed.
What you want to do is copy your Outlook PST file which contains all your emails, calendar appointments, tasks, etc. that you typically use in Outlook. This is normally a very large file, and sometimes is hard to find on your system. The following link explains how you can find this PST file and back it up.
Next, you probably want to avoid having to enter all your various email settings again into Outlook to download and send messages. To do this, you can use the information available on that same link previously mentioned which explains how to backup and restore your email settings in Outlook 2007.
Finally, if you have “rules” defined in Outlook, you can export them following the instructions on this link. With these three bases covered, you should be ready for the Windows 7 clean install and can restore Outlook to its original condition after the upgrade.