Gilmore,
Over the course of the last several months demos on the Pub have fluxuated between working and not working. The last that I was told was that they would work, but for only brief periods up to 2 minutes. Make sure to follow the correct procedure for recording and playing back a demo:
1. in the game, bring up the console with the ~ key
2. Type record "demoname"
3. when finished type "stop" in the console and the demo will be saved to your DoD:s folder with a .DEM extension
4. to play the demo go back the console and type "playdemo" and then the filename you used.
If one of our Steam Technicians has any more input on this issue then please elaborate.
If in case the demos do not work, then you might think of using an alternate Program to record your demos. The link provided is to the "OBS" Open Broadcaster Software website. Its totally free and pretty easy to use. I prefer it to the steam demos especially for making videos. Several other Unit members use it so if you are interested please ask around.
As to your second issue, it sounds like maybe an error with windows configuration of the mic or the drivers. Try to update the mics drivers, Also, perform a Windows Update to catch any other software issues. If those do not work, try uninstalling the microphone and rebooting the computer and letting windows reinstall it, sometimes that clears up issues. Please list the mic you are using as well.
Again, if anyone else has anything to add them so so by all means.