I cannot use '--color' option

[HIDAI Shigeyuki]

Hello Sir,
I am a user of Grep for Windows Version 2.5.1a.
Could you please give me some pieces of advice why I cannot use '--color' 
option?

C:\Program Files\GnuWin32\bin>grep -E --color "like[sd]? to" st345\*.txt
st345\st3.txt:   All young people like to have their own money, so they can 
go o
ut with their friends or buy new things. Most American kids get a little 
money f
rom their parents every week, but often it's not enough. So it's very common 
for
kids to get more money by doing some kind of work in their neighborhood.
st345\st3.txt:l It's good because most kids don't like to work.
-The rest of the result is omitted.-
------------------------------
HIDAI, Shigeyuki
address@hidden
address@hidden
Setagaya Junior High School
attached to Tokyo Gakugei Univ.
phone (03)5706-3301
fax (03)5706-3340