Fresh-faced, all-American performer with strong stage experience. Armstrong was sympathetic as the new wife whose presence disrupts the harmony of a close-knit group of friends in Alan Alda's "middle ages" comedy, "The Four Seasons" (1981). She also appeared in the hit TV miniseries "Lace" (1984) as Judy Hale, a magazine publisher and one of the three women Phoebe Cates rounds up in her quest for her mother. Armstrong's film work of the same period includes a starring role in the flat "Jaws 3-D" (1983), playing Tom Hanks' ex-girlfriend in the comedy "Nothing in Common" (1986) and Elaine in