no sound on entire computer

I installed Audacity 2.0.5 and from that moment, no sound at all works on my computer: not even blip prompts. The sound card and all drivers are good. The speakers and headphones are all good. Any thoughts?

If you have just connected a USB microphone, turntable or cassette player, see: .

If that does not help, please tell us what version of Windows you have. On Vista and later you can select the default playback device in Windows Sound .