Recording sound from a stereo

Hi, I am trying to record my cassettes to my computer so I can make a cd from them. I have Musicmatch jukebox. And Real player.
I also have windowsXP. I set the sound on recording. I have a cable to hook into the stereo back. have all kinds of in lines, and out lines. I have the cable inserted into the in plug on sound card. can you help.