If you have replaced the motherboard with a non-standard one from Dell then the driver no longer applies to the motherboard. I can help you find your driver and get you on your way to having audio if you can post your motherboard model. If you do not know then download this program (HWmonitor) or (Speecy). Choose one only, Speecy is more user friendly but sometimes it gets the temperatures wrong but HWmonitor is quite accurate but not that good looking:
Is this a laptop/notebook? If I am reading this correctly, your motherboard model is 0MD666? If you could could you post up a printscreen/photo of CPU-Z showing that information, I want to make sure I get you the right driver. It also wont hurt if you do download one of the programs I have listed just to confirm the motherboard.
Also you may want to try and download this, this here is a universal Realtek AC'97 driver so it may work if your computer audio driver is made by realtek:
This is a laptop.
Yeah ... 0MD666 is the model for my motherboard as told by CPU-Z.
I will just install those 2 softwares for system info which u told me and will let u know.
Meanwhile ,can you tell me you email ID wherein I can send u the screenshot as here in this column I can't see option of pasting/inserting the screenshot
Did the computer store replace your motherboard with the exact same model?
I read upon this online, it seems for your laptop and most other dell laptops you must install the drivers in order. 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.
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. Is your speaker icon in the corner have an x on it? If so it needs a driver however if it does not have an X it may be disconnected.
Before you uninstall the drivers try this first, using the link below this download the audio driver and before installing it uninstall all other audio drivers you have installed prior to this one's installation.
Am not sure if the computer store put up an exact same model or not .
Might be this is the issue as even after installing the drivers you told ,it didn't worked for me
......Anyways ,is there some way by which I can get the audio in my laptop even if the motherboard is not same as original..........not sure if I there is any possibility that I can put in some external device [or audio card sort of stuff] by which I can get the voice again.
Well can you go back to the computer store and ask them for the model of the motherboard? If they did replace the model they should have told you about it since your drivers would be completely different.