PC World: Hate it or love it, there's a good chance that you use Microsoft Outlook, still the most popular e-mail client on the planet. Outlook 2010 for Windows was just released, but only to businesses, who may take a while to switch to the new version. Office 2010 won't be available to individual users until later this spring.
PC World: A clean Windows 7 upgrade installation destroys all of your settings, requiring you to manually set up Windows all over again, reinstall all of your programs, and restore your data. It's a lot of work, but it results in a cleaner, more reliable PC. See How to Upgrade to Windows 7 for details.