First I should know what you want to record on your computer.
If it is your own voice, or a song from your hard disk or from any outside source such as RADIO, TV then you can use a AUDIO EDITING SOFTWARE, such as Nero audio editor. or Ulead Audio editor or Cool Edit Pro. These are all Audio Editing Softwares.
With this software you can record any thing in your computer.
You will have to use the LINE IN For the source or a MICROPHONE and LINE OUT to hear what you are recording in your PC.
Let me know if this has solved your problem or what you ment by your question.