Originally Posted by DjNDB
Okay, then we know that your prefs.prop has been corrupted. You can try right-clicking it to restore a previous version, from before the settings were lost. That should in theory also still have the information needed to access the savegames.
Worked for me. Put me on a bit of a downer when this happened. No amount of reinstalling or copy-paste to anywhere worked, but I was able to restore without a problem and BINGO!!! Signed up just to post a thanks.
edit: Sorry it didn't work for you Scorcher.