My VAIO does not output any sound from speakers or headphone output

First the basics:

1. Check if the volume is not muted. Fn-F3 mutes or unmutes the sound on VAIO models which do not have a designated Mute button.
2. Check if the volume is not set to minimum. Use Fn-F4 (or volume keys next to the keyboard) to set the volume higher.
3. If you are using an application that has its own volume control, check if the volume is turned up.
4. If headphones are connected to the headphones jack, the internal speakers will be disabled.
5. If external speakers are connected, make sure they are switched on.

Advanced:

1. If you have recently updated your sound card drivers, make sure you have correctly followed the installation instructions. Sometimes the previous version needs to be uninstalled first.
2. Check the downloads section for your VAIO Model if there are driver updates available.
3. If the problem only started very recently, you may consider restoring the system to a date before the problem started.