If that does not work your problem is that the motherboard model is completely different or wherever you took your laptop to get serviced the person forgot to plug in the speaker wires into the motherboard. So I know it may be quite a bit of work on your side but you may need to uninstall all drivers and download the new drivers online and install them in order. I read upon this online, it seems for your laptop and most other dell laptops you must install the drivers in order.
Did the computer store replace your motherboard with the exact same model?
