Heeeeelp MAC Probs!?

Being posted on behalf of a friend..I have a lovely 12" G4 Titanium laptop. Bought it second hand a couple of years back from my digital printer in London. I trust him and he gave me a good price. So far so bloody wonderful. Except for the fact that ALL applications would quit "unexpectedly" for no good reason I could ascertain. You put up with it. What else could I do? At the GENIUS BAR at the MAC shop in London they suggested I reinstall the system and all my software. Problem was all my software were basically gifts from the universe and the installation software, if I ever had it, was in London...far away from where I am now. So I go to another MAC shop and the guy says he can do a re- installation of the system for �15. FAB! But now none of my apps will work, he didn't put my photos back on and I can't even sign in to my broadband! HELP! IS there a MAC wizard out there? I cannot live with out my own computer! My partner has a PC laptop and anyone who is a MAC person knows what 2do