This shouldn't really bother people but it does bother me. I cant seem to hear the TOCW beeping sound, and I don't know if I've done something right or something is wrong. Even if I know its not configured for takeoff, I still won't get the beeping. Any ideas?

Do you get other flightdeck sounds (switch movement clicks, flap lever movement, etc)? If not, make sure the sound device you are using is correctly assigned in the options menu in the CDU.