Audio driver working but no sound

[prototype18]

Hi Guys . I recently updated my old comp from XP to WIN 7. After installing win 7 it auto installs HD audio.. HD audio drivers are ok but no sound. It says speakers /headphones are not plugged in .

Reinstalled the drivers but still no response. What to do

 

[RealBeast]

Laptop or desktop, if desktop does it have an audio card, onboard audio, or both? What motherboard model?

 

[prototype18]

Motherboard is K10N78M Asrock .

http://www.asrock.com/mb/overview.asp?Model=K10N78M

I downloaded driver and installed ... After installing the same thing. No headphones plugged in and it says driver are working.

I have 2 computers like this and the other one audio works with win 7.

This one works only with XP

Edit : No audio card