An important Q. abt the windows dialer

I have a problem that when I dial a phone no. from windows 2000 or any windows dialer then then phone no of my line is displayed on the CLI screen of target party.This is very strange with me bcoz I don’t want this.so pls help me that any hack like or any software I can install on my machine then this is done again that my phone no. is displayed hidden on target parth.Pls help me.