FARR is only really meant to index a relatively small amount of folders (like start menu, program files folder, and perhaps your "my documents" folder), since in the current versions it will always re-scan all the folders every time you search. This works OK most of the time because of windows filesystem caching, but still...
You really ought to check out locate32
. It works by indexing your drives (which is pretty fast), and afterwards it can
locate things more or less instantaneously. REALLY good stuff.