I record streaming audio from the Internet, but I use my PC's audio (RealTek on this machine) and usually Goldwave. As previously mentioned Audacity will also record from the PC's sound.
You have to have the "Stereo Mix" (called "System Mixer" on older systems, and SoundBlaster calls this function "What You Hear") set as the default recording device, in the Sound Panel/Recording Section.
Many PC's have this but it is not enabled (or displayed) in the Control Panel/Hardware and Sound and finally the Sound/Recording Panel. If it is not displayed, RIGHT click in an empty space in the panel and then LEFT click to display Disconnected and Disabled Devices. If the Stereo Mix now shows up you can enable it and make it the default recording device.