What files to backup?

I plan on doing (another) OS install shortly. Which files do I need to backup in the ProSeries program directories to assure that when I reinstall the program, and copy back the "backed-up" files, that I have retained all my e-filing and PPR status?I thought that the status of a PPR return was retained in the tax return data file, but I'm not so sure of that. I don't want to find out I can't print any PPR returns that a already paid for when I do my reinstall.