Why has the sound stopped working on my ISeries or CSeries?

If the sound has suddenly stopped working then the most likely solution is that the audio safety setting in the I-Series Control Center/C-Series Hardware Options has become unchecked by an update or another program. 

1. Open the Control Center (or C-Series Hardware Options) .
2. Select Safety.
3. Make sure the Audio and Temperature safety settings are both checked.

For ISeries+ devices, check that it was not switched to headphones. 

1. Select the speaker icon in the Windows toolbar.
2. Make sure it says Speakers (Realtech High Definition Audio).  If it says Speakers (Tobii I-Series Ext. Headphones), select the drop down arrow and switch it to Speakers (Realtech High Definition Audio).