The following example searches forward through the document for the word "aspirin." When the end of the document is reached, the search continues at the beginning of the document. If the word "aspirin" is found, it's selected.
With Selection.Find
.Forward = True
.ClearFormatting
.MatchWholeWord = True
.MatchCase = False
.Wrap = wdFindContinue
.Execute FindText:="aspirin"
End With