Another option is to dump windows all together and use Linux. We have 4 desktop computers and one old computer we use as a server in my home. Three dual boot with windows/Linux (kids and wife) and Linux only on mine. The rule is all email, web surfing and instant messenger is done using Linux only. I never have to worry about worms/viruses/spyware/slow downs it just works. The best thing is Linux is free and easy to install and comes with everything most of us need like free antivirus, firewalls, openoffice (just like MS Office), firefox, thunderbird, free photo editing/management programs and more... everything most people need. Unfortunately commercial games do not work nor tax programs thus the need for windows for my kids and wife and even they use Linux way more than windows. Zero learning curve going from windows 98/XP too. This may sound strange but you can also live boot into SimplyMepis or PCLinuxos the versions we use at home to test everything on your computer before installing them.
For the server I use SME server a totally free small business Linux server designed for business use but works great in the home too. I share one dialup connection and record TV/music to the server and stream those movies, music, pictures too all computers in the house. I could not be happier. Even at work they dumped small office server and upgraded to SME Server for $0. Anyone else using Linux instead of windows?