I faced this serious issue recently, where I could not call anyone on Skype or Gotomeeting.
These are the things that I have followed
- Uninstall and reinstall realtek driver
- Check all other audio mixer settings
- Changed Audio Plug, front and back
Nothing worked, and I thought my audio card has completely gone, but then I checked the realtek HD audio manager and disable the noise cancellation and echo cancellation.
Wow, it just worked, I made test calls and test recording it all worked fine.
Then again, I enabled the noise cancellation alone and left echo cancellation unchecked.
So, Try the same and you may be able to make it work.