First of all make sure that your speakers are connected and connected inthe speaker out jack on the back of your soundcard.  Also make sure your speakers are on and turned up.  Another way to turn the volume up is by clicking the speaker icon in the bottom right hand corner of the desktop.  Make sure "Volume Control" is in the middle or higher.  You may also want to download the latest drivers for your soundcard at the cards manufacter's website.  If you are  not hearing sounds correctly, you may have a "half duplex" soundcard.  Half duplex acts sort of like a walkie talkie, another words you can do only one thing at a time in reguards to sound.