Which fractions? If it's 1/4, 1/2, and 3/4, then the likelihood is that (a)
you have "Fractions (1/2) with fraction character (½)" enabled on the
AutoFormat As You Type tab of AutoCorrect Options, and (b) the font you're
using doesn't contain Unicode characters 00BC, 00BD, and 00BE (ASCII 188,
189, 190).
--
Suzanne S. Barnhill
Microsoft MVP (Word)
Words into Type
Fairhope, Alabama USA
http://word.mvps.org