You can do a targeted Update Statistics on single tables, the BoL should help lookup the UPDATE STATISTICS TSQL page.
You can I beleive run an EXEC sp_updateStats in line as well.
however I would also suggest that a Rebuild of indexes be run on a weekly basis during quiet times, 12-5am local is generally a good window.
There are also targeted index rebuild scripts available on line that will hit the worst offenders on a nightly basis (say over 60% fragmentation).
You can rebuild Nonclustered Indexes on the fly but it will impact perfomance a little using something like
ALTER INDEX <index> ON <Table> REBUILD (WITH ONLINE=ON)
(check the syntax in BOL).
I wouldnt recommend doing this with a clustered index though.
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SSC Guide to Posting and Best Practices