"
C cassette player" - I wasn't sure if you meant some special device, but you just mean "cassette player" do you?
jpk70 wrote: I want to record all the sounds which are currently coming from my computer. From Videos, microphones, internet radio, maybe a CD player attached to computer...
There's a distinction to be made here:
Internet radio, Windows Media Player, and such like, = "sounds playing on" / "sounds coming from", your computer.
Microphones, attached CD players and the like = external devices. These may play
through the computer, but the sounds do not come
from the computer.
It
may be possible to record external devices using "Stereo Mix", but that is not the best way to do it.
When recording external devices (such as microphones, CD players, cassette players) the sound card should be set-up to record from the input that is being used. Typically on a full size computer this will be the "Mic" input for microphones and the "Line" input for cassette players and similar equipment.
For recording sounds that are playing on your computer (such as internet radio and other audio applications that are running on the computer) it may be possible to record these by setting the sound card to record "Stereo Mix". Not all computers support the stereo mix option, but most XP machines do.
The first part of setting up the recording input for Audacity is to select the correct recording and playback "devices". Usually these will be correctly selected automatically, but can also be set manually in "Edit menu > Preferences > Devices".
Depending on the sound card drivers there may be an option in the "Mixer Toolbar" to select the specific recording input that you want to use. To enable/disable the "Mixer Toolbar" go to "View menu > Toolbars".
If no recording input options show in the Mixer Toolbar, it's because your sound card does not support the method that Audacity uses to access the sound card features, in which case you need to just set the correct recording device ("Edit menu > Preferences > Devices"), then use the sound card's mixer/control panel interface to select the specific input source. The sound card interface is usually accessible on XP via a "loudspeaker" icon near the time/date on the desktop.