I like Avast for anti-virus and Zonealarm for Firewall, but lately I've been using Comodos security suite. It's free and from everything I've read (and seen) Comodos firewall is on par or better than...

Having two OSes on your system will not slow it down in any way. They must be thinking of "virtualization" where you install software that emulates a second computer, running one as the host and a...