If you are having trouble with your home recording setup, I always recommend ripping a .wav file from a cd you own and importing it into your audio recording software. Then hit play. If you don't hear anything, you may have problems with your outputs in your audio recording software.
If changing the outputs in the recording software doesn't seam to do any good, I use Windows Media Player and just play the cd through the cd-rom drive. This takes the software out of the equation. If Media Player doesn't play sound, you have a problem that you need to track down (which will hopefully be outlined in the following steps).

Graphic provided by DT_Chris from http://www.darktownstudios.com
H – As you can see in the Mona Lisa caliber graphic, the signal coming out of the computer is still a bunch of ones and zeros (or digital). This signal is probably passed through the same cable that sends the digital signal to your soundcard in the first place.
When troubleshooting problems with the output of your soundcard, keep the chain as simple as possible. Play a cd with Windows Media Player. If your soundcard has LEDs, see if these lights come on when the music is played.
I – Analog signal coming out of the soundcard – The soundcard has gotten the signal back from the computer and has converted it back to an analog wave signal. I would have drawn it so that this signal had has the same wave picture that you can see in “B”. Oh well. Too bad. Just remember this is an analog signal.
In my oversimplified graphic, I've left out the power amp for the studio monitor shown, but we can just assume that this studio monitor is powered (with the amplification built into the speaker).