Bruce must be busy with RL, but you can find that information two ways. FAHClient installs a shortcut to the "data directory" under FAHClient in the All Programs directory. You can also find it in the log that you posted:
melephant wrote:*********************** Log Started 2011-11-14T18:14:00 ************************
18:14:00:************************* Folding@home Client *************************
18:14:00: Website:
http://folding.stanford.edu/18:14:00: Copyright: (c) 2009-2011 Stanford University
18:14:00: Author: Joseph Coffland <joseph@cauldrondevelopment.com>
18:14:00: Args: --lifeline 2740 --command-port=36330
18:14:00: Config:
C:/Users/Mel/AppData/Roaming/FAHClient/config.xml
There are more files that just config.xml in that directory but to do what he asked, they should all be discarded (except perhaps config.xml, itself.
Actually, whenever you install, if the installer detects a previous version it asks if you want to uninstall. All you have to do is click the box telling it NOT to keep the data.