Good Samaritan needed for hopeful quick fix - Adobe CS4

I am helping a friend sound edit a demo video, which another person had edited in Premier 3 I believe. It is now on my friend's computer she has Premier as part of CS4 on a PC (lives in NJ) a program I have no experience in. I learned Avid years ago and stumbled through Final Cut a few times but haven't edited in years. My friend has the edited piece at her home in NJ on PC, I am a MAC user and don't have Premier but learned i can demo the new version for 30 days which I will do. Anyhow, I adjusted the sound on the final edit using my instincts, somehow, which was going well. She tried to correct a title where the picture was missing and now that has thrown most of the piece off sync. Things go missing we don't know why...multiple versions get saved and we are clueless....Also a sound bite is missing now and we can't find it. We have an idea what the problem is but it's the blind leading the blind. She knows less than I do. Now we have a demo that is dead in the water and all we wanted to do is fix the sound so that it wouldn't be awful. Apparently DVD's made from the original edit were really bad. It might just take a few clicks of the keypad to fix this all but I haven't edited in a long time and am not familiar with Premiers tools and am afraid I'd make a mess. I need to go back to school! Can anyone help??? Needy in NYC