Advice needed to secure my parents pc!

My brother knows virtually nothing about PCs. So I am the one that set his XP system up for him. At this point, he has aVast!, Windows Firewall and Windows Defender running on it. (He also does his surfing using Firefox.) I plan to add BOClean to it once the free version is available. And that's pretty much it...

 

I see only one little problem : your brother can't be your father and the thread was about parents. (j/k)

 

True. But I felt it was ok to keep it in the family...