No playback

I’m new to Cubase and recording in general and am trying to learn how to record some stuff using Cubase LE 5. I have a Lexicon Omega mixer, and I’m recording just any basic audio with a mic; I record a line an can see its taking but when I try to listen to what I recorded I can’t hear any playback audio. Whether I use headphones or not and at a very loud setting I can’t hear anything, but if I open an mp3 or anything I can hear it through my speakers, so what do I do?

Disable the Monitor Button on the track for playback.

The moniter button is already disabled; any other ideas?

Are the speakers connected to your Computer soundcard…? If so - connect them to your Lexicon.