The backing everything up, driving down to the store, buying software and then installing it is easiest thing to do? You really don't think there is an easier solution? I already told you this issue has been discussed and resolved on numerous forums for his age imac, with the exact same problems and I found them in a minute of searching google. I will not post the link because I don't think anyone needs me to hold their hand while crossing the street... but go ahead, suggest someone buy a piece of software that might not be compatible with his computer. No skin of my back.
This site has some of the worst advice from some of the least knowledgeable people who think they know everything I have ever witnessed.