won't record

I got Audacity exe installer 2.0.6 two days ago. It recorded streaming from the internet just fine. Now day three it won’t record. Streaming or music from computer. I’m not very computer savvy. Need help. I’m using windows 7

Does this tutorial from the Audacity Manual help: http://manual.audacityteam.org/o/man/tutorial_recording_audio_playing_on_the_computer.html