If you are using vista/windows 7 you may be able to restore the files from previous versions via file properties --> prevoius versions, rather than doing a full system restore.
You probably aren't in any trouble. Get the list of modified files, checking the modified by date will tell you which ones are which hopefully. Lastly, a system restore may not do the trick.
I installed as instructed and it works fine, but I realized after reading that I possibly selected to overwrite my original files rather than keep them, as was strongly disadvised? It had an option "No to all" so I chose that, thinking it meant don't overwrite. How much trouble am I looking at here? Would a system restore fix everything?
(Didn't know where to post so put it here as was suggested in the FAQ)