There are a lot of uses for being able to directly record the sound that your PC is making, and it’s relatively easy to do. This method does not require you to have to use any cables, it just uses the audio driver. That means that it’s not guaranteed to work as your driver may not support this feature, but most seem to.
First you need to open the Sound control panel applet, and go to the Recording Devices tab. Right-click and show disabled devices. You should now see a device called Stereo Mix or Rec. Playback or similar, if it’s disabled (greyed out and with a grey arrow pointing down next to the icon) then enable it and click OK to close the control panel.
To record I either use WaveLab (expensive, pro audio editing software) or when I’ve forgotten the dongle I use the Audacity (which is free, and works ok). I’m going to assume you don’t have WaveLab, so here’s how to record via Audacity:
Select Windows DirectSound as the Audio Host (dropdown on the left), and choose whatever recording device you enabled earlier – Rec. Playback in my screenshot above.
Audacity is now configured to record any noises your PC makes, which include notification beeps etc. So if you’re recording the audio from a webinar or something you might want to make sure you’ve muted all your other noises and closed other software aside from the one that’s going to be making the noises.
When you’re ready to record, just click the record button on the Audacity Transport Toolbar, and then join the meeting or start whatever software it is that makes the noises you want to record. If everything is working correctly you’ll see the waveform change in the main Audacity window, and can also choose Start Monitoring on the record meter in the Audacity Monitoring Toolbar.