A) I use: http://www.apowersoft.com/free-online-screen-recorder
run it direct from the web,click the “Start Recording” button. You can make it capture the screen and audio or just audio.
HINT: open Apowersoft, record a little bit of audio and then stop it again, THEN start Syrinscape, and you should be good to go. You’ll need to let Apowersoft install the virtual audio driver on your system.
IMPORTANT: Always test it’s recording correctly before you do something long and significant.
B) You can also use Audacity, it’s just a matter of working your way through one of the many reasonably helpful, tutorials you can find online. Like here: http://manual.audacityteam.org/o/man/tutorial_recording_computer_playback_on_windows.html