Hi straitsfan,

AFAIK there is no setting in Word for inserting two spaces after a period. In any event, that practice is a legacy from the days of typewriters with fixed-pitch fonts. In that era, the additional spaces made a great deal of difference in the text's readability.

As for using wildcards, the 'how' really depends on what you're trying to do. Word's help file has some useful pointers. Appropos your double-spacing after sentences, if you have a document with possible multiple spaces between sentences and between some words, but you want to have only one space between words and two between sentences, use a wildcard Find/Replace, with:
Find = ([!.][ ])[ ]{1,}
Replace = \1
Similarly, to ensure double spacing after sentences that are only followed by a single space:
Find = (. )([! ])
Replace = \1 \2
Do note, though, that this will also insert double spaces after any period followed by a space then any character that is not a space (eg Mr._X and Mrs._Y will become Mr.__X and Mrs.__Y (where the _ represents a space)).

Regarding the spell-check dictionary, you should check to ensure the relevant proofing tools have been installed. If they have been, you may need to repair your office installation.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]