installing SP2

I HAVE WINDOWS XP..I'VE TRIED TO INSTALL SP2 BUT IT MESSES UP MY SOUND
EVERYTIME..LIKE NO SOUND AFTER INSTALLATION..I'VE ALSO JUST INSTALLED AVG
FIREWALL PROTECTION ...I'V TRIED TO DEFRAG. AND IT SAYS I HAVEN'T ANY MORE
ROOM.AND TO EMPTY MY FILES..I DON'T KNOW HOW TO DO THAT..I HAVE ALOT OF SONGS
DOWNLOADED AND PICTURES. COULD THAT BE TAKING UP ALL MY SPACE?