Hi robrowald
Thanks for your mail. This can be done but it really depends on the soundcard you are using in your PC and not trakAxPC.
Your soundcard must have a stereo mix option in order to record the playback in trakAxPC - http://www.stereo-mix.com/about-stereo-mix
There are a couple of good tutorials on YouTube that shows you how to record what is coming through your speakers/headphones (stereo mix) and recording with your Microphone.
Windows Vista
http://www.youtube.com/watch?v=Fu371l4lFjk
Windows 7
http://www.youtube.com/watch?v=Wy98HMqcYw4&feature=related
I hope this helps and please do not hesitate to contact me with any questions.
Best regards
Cormac