There was a thread here in April about the same problem:
http://groups.google.com/group/microsoft.public.word.tables/browse_thread/thread
/9c74a98c7870c8b4/84a6c52cc1d0ac81?lnk=st&q=&rnum=1&hl=en#84a6c52cc1d0ac81
Try looking for an updated display driver.

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Hope this helps.
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Doug Robbins - Word MVP
> word 2007 -- when I click on a cell to edit info - the entire row and/or
> column turns blue (dark) as if it were selected -- I can type new info --
[quoted text clipped - 3 lines]
> Word Options and cannot find a setting that might affect this...
> Suggestions???? -- Thanks