A family of Microsoft word processing software products for creating web, email, and print documents.
Row.HeadingFormat is the flag that indicates that Word thinks the row is a table heading that repeats on every page. If you have some other definition of a table heading, you'll need to say what it is - perhaps you just want to change the first row of each table, I don't know:
For Each Table In ActiveDocument.Tables
Table.Rows(1).Range.Find.Execute FindText:="$", _
Replace:=wdReplaceAll, _
ReplaceWith:=ChrW(160) & "$" & ChrW(160)
Next
Enjoy,
Tony