Audio played can't be heard

Aira2001 - Updated on Aug 5, 2017 at 04:41 AM
The OS on my PC is Windows7 Ultimate. Though the audio driver is totally updated and the sound card works fine too, audio played can't be heard. I've tried connecting an external speaker too but it shows "not plugged in" despite of being plugged in properly. What should I do now?

Windows7 Ultimate
Intel Core Processor