By SPS3 I assume you mean MOSS 2007? Have you done all of the
pre-requisites (added content sources, run an index on the sources, etc)
and do you get any results  for non-keyword searches  under the same user?

Did u make search  Center and check if u add the correct path in search setting?
and check if u crawl that the crawl log has no errors

I could also be a sql permission issue as well which can be difficult to
track down

Another thing to check is do any of your documents actually contain any
Office property keyword  that match your search  criteria or have you
associated any Best Bets (pages, lists, content) to the keyword you are
searching for and then run a crawl?

I think there is something broken in
my test SPS environment. The search  works fine in production so I think
I'll just live with the broken test box.