Most likely because it contains no actual explanation of what the problem is, and no log file from the recording session.
From watching the video, it looks like your mic is active but is not being recorded, even if your desktop is... but normally a text write-up accompanied by a log, rather than an entirely undescribed video will get a better response. :)
In this case, please post a logfile from a recording session where the issue is occurring.
If you're using multi-track recording, please be aware that only ONE audio track can play at a time; if you are recording Desktop to track 1 and Mic to track 2, you can pick one or the other, but not both.
Normally to fix that, you have both Mic and Desktop recording to Track 1, Desktop to track 2 (so boxes 1 and 2 checked for Desktop), with Mic recording to track 3 (so 1 and 3 checked). At that point Track 1 is your Mixdown track, while 2 is your clean desktop, and 3 is your clean mic for later editing.