Take a look at Linux Mint. Good GNU/Linux distro to start with. Transition from XP should be smoother. Bundled VLC player can play almost all media files . A little bit learning curve though. Specially the way programs/apps are installed.
Avira Antivir v10 free for Home user
(Some false positives although)
Kaspersky is a pain
(Loads of false positives. Unable to protect from USB virus)
Why use when better alternative is available at no cost?