Wish I hadn't!! Tried download from Vuze (eeekkk!) In a mess now!

Well - I say 'I' - actually my son! He was after a particular piece of software which appeared to download fine through Vuze but to install it you had to change something in the Terminal??? He went ahead and fiddles about and blast the Mac screamed for help! I had to restore the while lot from OS disc which took about 4 hours! After reloading my Entourage was a bit of a mess - but managed (I think) to sort that. But we have also noticed now that certain programs refuse to open?? Vuze being one, Entourage was another which I resintalled. Don't feel at all confident about my Mac now. I trashed all to do with Vuze in the hope that I could reinstall it - but when the installation completes - open Vuze and it immediately refers you back to the web page? Cant get any further than that. Have a got a disc utility - I can't even show you now what he did as after the restore the trash bin was emptied?? Anyone help? Any Vuze buddies there? Any patient restores that can help in a way that doesn't take 4 hours? Thank you. SM