Im new to this and signed up cos im having problems with my imac remote, AND keyboard, Sorry if this is in the rong forum if it is please tell me

Anyway, the problem im having is my imac remote has stopped working and only the play/pause button is working, i thought dang ok i will replace it and wnt on to try use my keyboard to control my music, but again it wont let me control volume or tracks

If anyone knows a likely or common cause and details of how to fix please tell me

Thanks very much, Toffy